Systematic Population ScreeningUsing Biomarkers and GeneticTesting Identifies 25 of the UKPediatricDiabetesPopulationWithMonogenic DiabetesDiabetes Care 2016391879ndash1888 | DOI 102337dc16-0645
OBJECTIVE
Monogenic diabetes is rare but is an important diagnosis in pediatric diabetesclinics These patients are often not identified as this relies on the recognition ofkey clinical features by an alert clinician Biomarkers (islet autoantibodies andC-peptide) can assist in the exclusion of patients with type 1 diabetes and allowsystematic testing that does not rely on clinical recognition Our study aimed toestablish the prevalence of monogenic diabetes in UK pediatric clinics using asystematic approach of biomarker screening and targeted genetic testing
RESEARCH DESIGN AND METHODS
We studied 808 patients (795 of the eligible population) lt20 years of age withdiabetes whowere attending six pediatric clinics in SouthWest England and TaysideScotland Endogenous insulin production was measured using the urinary C-peptidecreatinine ratio (UCPCR) C-peptidendashpositive patients (UCPCR Dagger02 nmolmmol) un-derwent islet autoantibody (GAD and IA2) testing with patients who were autoan-tibody negative undergoing genetic testing for all 29 identified causes of monogenicdiabetes
RESULTS
A total of 25 of patients (20 of 808 patients) (95 CI 16ndash39) had monogenicdiabetes (8 GCK 5 HNF1A 4 HNF4A 1 HNF1B 1 ABCC8 1 INSR) Themajority (17 of20 patients) weremanagedwithout insulin treatment A similar proportion of thepopulation had type 2 diabetes (33 27 of 808 patients)
CONCLUSIONS
This large systematic study confirms a prevalence of 25 of patients with mono-genic diabetes who were lt20 years of age in six UK clinics This figure suggeststhat sim50 of the estimated 875 UK pediatric patients with monogenic diabeteshave still not received a genetic diagnosis This biomarker screening pathway is apractical approach that can be used to identify pediatric patients who are mostappropriate for genetic testing
1Institute of Biomedical and Clinical Science Uni-versity of Exeter Medical School Exeter UK2Exeter National Institute for Health ResearchClinical Research Facility Royal Devon and Exe-ter NHS Foundation Trust Exeter UK3Blood Sciences Royal Devon and Exeter NHSFoundation Trust Exeter UK4Molecular Genetics Laboratory Royal Devonand Exeter NHS Foundation Trust Exeter UK5Exeter Test Group Institute of Health ResearchUniversity of Exeter Medical School Exeter UK6Department of Paediatrics Northern DevonHealthcare NHS Trust Barnstaple UK7Department of Paediatrics Royal Cornwall Hos-pitals NHS Trust Truro UK8Department of Paediatrics Royal Devon andExeter NHS Foundation Trust Exeter UK9Children amp Young Peoplersquos Outpatient Depart-ment Plymouth Hospitals NHS Trust PlymouthUK10Department of Paediatrics South DevonHealthcare NHS Foundation Trust Torquay UK11Child Health School of Medicine University ofDundee Ninewells Hospital amp Medical SchoolDundee Scotland UK12Division of Cardiovascular amp Diabetes Medi-cine School of Medicine University of DundeeDundee UK
copy 2016 by the American Diabetes AssociationReaders may use this article as long as the workis properly cited the use is educational and notfor profit and the work is not altered More infor-mation is available at httpwwwdiabetesjournalsorgcontentlicense
See accompanying articles pp 18541858 1870 1874 1889 1896 19021909 and 1915
Maggie Shepherd12 Beverley Shields1
Suzanne Hammersley2 Michelle Hudson2
Timothy J McDonald13 Kevin Colclough4
Richard A Oram1 Bridget Knight2
Christopher Hyde5 Julian Cox6
Katherine Mallam7
Christopher Moudiotis8 Rebecca Smith9
Barbara Fraser10 Simon Robertson7
Stephen Greene11 Sian Ellard1
Ewan R Pearson12 and
Andrew T Hattersley1 on behalf of the
UNITED Team
Diabetes Care Volume 39 November 2016 1879
PREC
ISIONMED
ICINE
Monogenic diabetes is often not recog-nized in children or adolescents andmisdiagnosis as type 1 in these individ-uals is common (1ndash8) Making the cor-rect diagnosis of monogenic diabetes isvitally important because the manage-ment of the most common subtypes(GCK HNF1A and HNF4A maturity-onsetdiabetes of the young [MODY]) is mark-edly different from that for type 1 diabe-tes (910) Molecular diagnosis improvesclinical care by confirming the diagnosisaiding prediction of the expected clinicalcourse of the disease and guiding appro-priatemanagement and family follow-up(10ndash12) Because of the predominanceof type 1 diabetes in children the poten-tial significance of a parent with diabetesor possible noninsulin dependence maybe overlooked This leads to unnecessaryinsulin treatment with a mean delayfrom diabetes diagnosis to the correct ge-netic diagnosis of 93 years (K ColcloughS Ellard unpublished observations)(based on 1240 patients who were ini-tially diagnosed with diabetes20 yearsof age but subsequently received a ge-netic diagnosis of GCK HNF1A or HNF4AMODY)The present approach to diagnosing
monogenic diabetes requires clinicalrecognition by an alert health care pro-fessional and subsequent genetic testingBecause genetic testing for monogenicdiabetes is now widely available world-wide the major barrier is clinician recog-nition (although costs and lack of medicalinsurance coverage of genetic testingcan also limit who is tested) Despitethe availability of guidelines advisingwhen a diagnosis of monogenic diabe-tes in children should be suspected (10)genetic testing is under-requested Wehave shown that the underdiagnosis ofMODY in some regions in the UK re-flects reduced testing rather than inap-propriate testing (13)Biomarker tests can help to identify
appropriate candidates for genetic test-ing for monogenic diabetes avoidingreliance on clinical recognition Thesebiomarkers are most useful in enabling afirm diagnosis of type 1 diabetes to bemade obviating the consideration of ge-netic testing The lack of significant en-dogenous insulin production (stimulatedserum C-peptide level 200 pmolL) isseen in type 1 diabetes outside the honey-moon period Urinary C-peptide creatinineratio (UCPCR) provides a simple stable
reliable noninvasive measure which canbe tested on a sample posted from homedirect to a laboratory (1415) and hasbeen validated against the mixed-mealtolerancetest (16)AUCPCR$02nmolmolindicates the presence of endogenousinsulin and has been used to differenti-ate patients with MODY from those withtype 1 diabetes5 years after diagnosis(17) Islet autoantibodies are found inthe majority of patients with type 1 di-abetes especially when measured closeto diagnosis and are an excellent discrim-inator between type 1 diabetes andMODY (18)
A large number of studies have triedto assess the prevalence of monogenicdiabetes in the pediatric population(Table 1) however the majority ofthese studies did not use a systematicapproach or were limited to single clinicpopulations A further limitation is thatno studies to date have investigated allthe causes of monogenic diabetes (Table1) Only three studies have systematicallyscreened large populations as follows1) a US multicenter systematic study(SEARCH) identified a minimum preva-lence of 12 with MODY (1) and a fur-ther 02 with neonatal diabetes (19)2) a Norwegian nationwide study identi-fied a minimum prevalence of mono-genic diabetes in children of 11 (2)and 3) a Polish study identified a mini-mum prevalence of 31ndash42 (7) Othersmaller studies (4820ndash22) report screen-ing or assessment of single pediatric clinicpopulations and although islet autoanti-body negativity is often used to identifychildren who could benefit from genetictesting the screening and testing strate-gies are variable with estimates of prev-alence up to 25 Surveyquestionnaireor epidemiological data relying on physi-cian reporting and recognition of the clin-ical features of monogenic diabetes inpediatric populations statewidely varyingprevalences of 06ndash42 (723ndash27) How-ever these approaches do not involvesystematic screening and thereforemay be considered less accurate
We report the first prevalence studyof monogenic diabetes in the UK pedi-atric population using a systematicscreening algorithm and genetic testingfor all subtypes of monogenic diabetes
The aim of this study was to identifythe prevalence of monogenic diabetesin the UK pediatric diabetes populationby systematic screening
RESEARCH DESIGN AND METHODS
Study EligibilityAll patients with diabetes who were20 years of age attending one of sixpediatrictransition clinics across SouthWest England and Tayside Scotlandwere eligible to take part Ethical ap-proval was granted by the National Re-search Ethics Service Committee SouthWestndashCentral Bristol Participants under16 years of age were asked to provide as-sent and their parents provided consent
The total number of potential recruits(n = 1016) was ascertained by the localpediatric clinical teams from their clinicrecords (ie all their patients with dia-betes who were 20 years of age wereidentified 779 in South West Englandand 237 in Tayside) Informed consentwas obtained by a member of the re-search team prior to data collectionand participants $16 years of agewere asked to provide consent them-selves and if they lacked capacity theirparents were asked to provide consentTime from diagnosis was not an exclu-sion criterion Data collection includedthe following sex ethnic group currentageage at diagnosis initialcurrenttreatment time to insulin treatmentfamily history of diabetes most recenthighest HbA1c level heightweight at di-agnosis and time of recruitment and thepresence of learning difficulties or deaf-ness BMI was reported as age-adjustedpercentiles to enable comparison acrossage groups (28)
Screening MethodThe study comprised three potentialstages that systematically identifiedthose patients who were eligible for ge-netic testing (Fig 1)
Stage 1 consisted of a urine sample forthe measurement of UCPCR (14ndash16) Par-ticipants receiving insulin treatment wereasked to mail a urine sample collected 2 hafter the largest meal of the day that con-tained carbohydrate to a single laboratoryat the Royal Devon and Exeter NHS Foun-dation Trust Participants with endoge-nous insulin production ascertained byUCPCR of $02 nmolmmol and thosenot receiving insulin treatment progressedto stage 2 of the study Patients with aUCPCR02 nmolmmol indicating insu-lin deficiency were considered to have adiagnosis of type 1 diabetes (1416)
Stage 2 comprised a blood samplethat tested for the presence of islet
1880 UK Screening for Pediatric Monogenic Diabetes Diabetes Care Volume 39 November 2016
Table
1mdashAppro
ach
esuse
dto
identify
monogenic
diabetesin
pediatric
populations
Typeofstudy
Country
Area
Initialcohort(n)
Cohortcharacteristics
Testingstrategy
(subgrouptested
)Gen
estested
Prevalen
cein
genetically
tested
Minim
alprevalence
of
monogenic
diabetes
Reference
System
aticstudiesordered
bynumber
instudy
Multicen
terpopulation
based
US
6centers
California
OhioH
awaii
South
Carolina
Washington
596
31)
Diagn
osed20
years
1)AB-ve(3
2)fasting
C-pep
tide$08ngmL
(n=58
6)
1)HNF1AH
NF4A
GCK
1)84(47586
)12
1
2)Diagnosed6months
2)Diagn
osed6months
(n=7)
2)KC
NJ11
INS
ABCC8
2)71
4(57)
02
(total14)
19
Nationwidepopulation
based
Norw
ayNationwide
275
6New
lydiagnosed
age0ndash14
years
1)AB-ve(3
2)and
affected
paren
t(n
=46
)1)
HNF1AH
NF4A
MIDD
1)13
0(646)
11
2
2)AB-veHbA1c75
(58mmolmol)and
notreceivinginsulin
(n=10
)
2)GCK
2)30
0(310)
3)Diagn
osed12
months
(n=24
)3)
KCNJ11
ABCC8
INS
3)16
6(424)
Epidem
iologicald
ata
nationwidegenetictest
results
Poland
3centers
Lodz
Katowice
Gdan
sk
256
8Age
0ndash18
years
1)AB-ve
affected
paren
tnoninsulin
dep
enden
t1)
HNF1AH
NF4A
HNF1B
321(100
311)
31ndash42
7
2)HbA1c75
(58mmolmol)
2)GCK
3)Diagn
osed6months
3)KC
NJ11
ABCC8
INS
4)Syndromicdiabetes
4)WFSAlstrom
Singleped
iatricclinic
population
US
New
York
939
ClinicaldiagnosisT1D
AB-ve(3
3)pluseither
GCK
86
(558)
05
4
Age
6monthsto
20years
HbA1c7
(53mmolmol)and05
unitsinsulinkgday
1year
postdiagnosis
C-pep
tidepositive
or
3genFH(n
=58
)
HNF1A
Pediatricclinicsin
single
city
Australia
Sydney
497
1)Clinicaldiagn
osisT1D
AB-ve(3
4on
2occasion
s)(n
=19
)1)
HNF1AH
NF4A
2)INSKC
NJ11
5(119)
12
20
2)Diagnosed6monthsto
16years
Singleped
iatricclinic
population
Spain
Madrid
252
1)Clinicaldiagn
osisT1D
AB-ve(3
5)(n
=25
)1)
HNF1AH
NF4A
80
(225)
08
8
2)Diagnosed6monthsto
17years
2)KC
NJ11INS
Pediatriccliniccase
histories
New
Zealand
South
Island
160
Pediatricdiabetes
18
years
AB-ve(3
2)(n
=4)
GCK
HNF1B
HNF1A
25(4160
)25
21
Con
tinu
edon
p18
82
carediabetesjournalsorg Shepherd and Associates 1881
1882 UK Screening for Pediatric Monogenic Diabetes Diabetes Care Volume 39 November 2016
autoantibodies (GAD and IA2) to identifythose with autoimmune diabetes Thistest was performed in all participantswith significant endogenous insulin levels(either a UCPCR $02 nmolmmol whilereceiving insulin treatment or not receiv-ing insulin treatment) If islet autoantibodyresults were available from previous test-ing these were used otherwise a bloodsample was taken for antibody testingPatients with GAD or IA2 levels 99thpercentile were deemed islet autoanti-body positive (18) and were consideredto have a diagnosis of type 1 diabetesStage 3 consisted of genetic testing in
participants who were UCPCR positiveand islet autoantibody negative DNAwas extracted using standard methodsfrom a blood sample that was usuallyobtained at the same time as the samplefor islet autoantibody testing Sanger se-quencing analysis of the HNF1A andHNF4A genes and dosage analysis bymultiplex ligation-dependent probe am-plification to detect partial and wholegene deletions of HNF1A HNF4A GCKand HNF1B was undertaken for all pa-tients with additional Sanger sequenc-ing analysis of the GCK gene undertakenfor patients with maximum HbA1c levelsof76 (60 mmolmol) This testingstrategywas performed initially becausethese are the most common genes im-plicated in MODY accounting for95of all MODY cases in the UK (13) andare amenable to treatment change Pa-tients with no pathogenic mutationidentified by Sanger sequencing andmultiplex ligation-dependent probe am-plification then underwent targetednext-generation sequencing to look for
mutations in 29 genes known to causemonogenicdiabetes and themitochondrialmutation m3243AG causing maternallyinherited diabetes and deafness using theassay published by Ellard et al (29)
Statistical AnalysisData were double entered onto a data-base and subsequently cleaned Dataarepresented as proportions andmedian(interquartile range [IQR]) where appro-priate because of the non-normality ofdata Prevalence was calculated as theproportion of patients with monogenicdiabetes out of the total number of pa-tients studied Data were analyzed usingStata version 131
RESULTS
A total of 795 of the eligible popula-tion (n = 808 of 1016) completed thestudy (Fig 2) Fifteen of these partici-pants had previously undergone genetictesting and were already known to havemonogenic diabetes (Table 2)
Patient CharacteristicsA total of 54 of participants were male(441 male 376 female) The median ageat study recruitment was 13 years (IQR =10 16) the median age at diagnosis was8 years (IQR = 4 11) and all individualsreceived a diagnosis of diabetes at6 months of age The median durationof diabeteswas 43 years (IQR = 16 79)The majority (788 participants [96]) ofthe cohort were white reflecting thepopulation demographics in these areasA total of 792 patients (97) were receiv-ing insulin treatment at the time of studyrecruitment including 4 patients whowere receiving treatment with insulin in
addition to metformin Twenty-five pa-tients (3) were noninsulin treated with11 patients receiving oral agents onlyand 14 were being treated withdiet alone The median HbA1c level was86 (IQR = 77 97 [70 mmolmol IQR =61 83]) and the median BMI percentilewas 79 (IQR = 56 94)
Stage 1 UCPCRA total of 547 of 817 patients (67)wereUCPCR negative (02 nmolmol) indi-cating insulin deficiency and weretherefore considered to have type 1 di-abetes and these individuals did notundergo further testing In addition261 patients (32) had significant endoge-nous insulin production ($02 nmolmol)this included 236 patients who weretreated with insulin and 25 patientswho were not treated with insulin
Stage 2 AntibodiesThe 253 patients with significant endog-enous insulin levels underwent isletautoantibody testing which included236 patients who were treated with in-sulin and confirmed to be UCPCR posi-tive through stage 1 of the study and17 patients who were not treated withinsulin Eight of 15 patients who hadpreviously received a diagnosis ofmonogenic diabetes did not undergo an-tibody testing (but none of these weretreated with insulin) and 9 patients didnot return their blood sample for anti-body testing
A total of 179 of 253 participants wereislet autoantibody positive confirming adiagnosis of type 1 diabetes Forty-fiveof these participants were positive toboth GAD and IA2 28 were positive toGAD only 21 were positive to GAD butIA2 was not tested for and 85 were pos-itive to IA2 only indicating the impor-tance of testing for both autoantibodiesThe 74 participants who were antibodynegative continued to stage 3 for genetictesting
Stage 3 Genetic TestingThe prevalence of monogenic diabetesin this UK pediatric diabetes popula-tion that was 20 years of age was25 (95 CI 15ndash39) A total of82 of 808 patients (101) had under-gone genetic testing and 20 of these(24 1 in 4 patients) had monogenicdiabetes (Table 2) Fifteen of 20 patientswere previously known to have mono-genic diabetes (7 GCK MODY 5 HNF1A
Figure 1mdashPathway of testing
carediabetesjournalsorg Shepherd and Associates 1883
MODY 1 HNF4AMODY 1 ABCC8MODYand 1 patientwith typeA insulin resistancedue to a heterozygous INSRmutation) and5 new cases of monogenic diabetes(3 HNF4A MODY 1 HNF1B MODY 1 GCKMODY) were identified during the studyOne of these patients had a dual diagno-sis of HNF4A MODY (heterozygous forthe pArg114Trp mutation) and type 1diabetes (GAD negative as defined inthis study as the 99th percentile andtherefore proceeded to genetic testingbut with a GAD titer of 259975th per-centile and a UCPCR of 021 nmolmol2 years after diagnosis and had receivedcontinuous insulin treatment from thetime of diagnosis) Patients with mono-genic diabetes were found in all six clin-ics with a prevalence varying between12 and 37To assess whether we had missed
cases of monogenic diabetes in thosewith islet autoantibodies 65 of 179 pa-tients with positive autoantibodies un-derwent Sanger sequencing analysis ofthe most common MODY genes (GCKHNF1A and HNF4A) no mutations werefound
Characteristics of Patients Negativeon Genetic TestingDiagnosis was not established using thistesting pathway in 62 participants whowere UCPCR positive islet autoantibodynegative and negative for mutations in
29 genes known to cause monogenicdiabetes Secondary causes of diabeteswere known in two individuals with apreviously recorded diagnosis of cysticfibrosisndashrelated diabetes Twenty-sevenof 62 of these patients (33 of the co-hort) met the diagnostic criteria fortype 2 diabetes (no monogenic or sec-ondary cause BMI $85th percentileand antibody negative [httpwebispadorgsitesdefaultfilesresourcesfilesidf-ispad_diabetes_in_childhood_and_adolescence_guidelines_2011_0pdf]) but were not assessed for insulinresistance or other metabolic features
Uncertainty over the diagnosis re-mained in 33 individuals (4 of thewhole cohort) The most likely diagnosisin these individuals was islet autoanti-body-negative type 1 diabetes becausethey were close to diagnosis (medianduration 08 years [IQR = 04 28]) andwere not overweight (median BMI in the51st percentile [IQR = 43 67]) Twenty-six of 33 of these individuals had a di-abetes duration of 3 years and socould be considered to be within thehoneymoon phase repeating testingfor the UCPCR in these individuals overtime could prove to be useful However5 of 33 individuals had a median diabe-tes duration of 61 years (range 5ndash10years) median BMI in the 53rd percentile(range 46th to 81st percentile) with a
medianUCPCRof 036nmolmmol (range021ndash127 nmolmmol) therefore thediabetes in these individuals should beconsidered atypical and not fitting aclear diagnostic category
Only 194 of the eligible patientswithin these pediatric diabetes popula-tions (n = 198) did not take part in thisstudy This included 13 known patientswith monogenic diabetes (10 patientshad GCK MODY and were thereforenot under the care of a diabetes team3 patientswith HNF1A and 1 patientwithWolfram syndrome) Therefore this co-hort was not biased to include all thosepatients with known monogenic diabe-tes The prevalence of monogenic diabe-tes in those patients recruited was 25comparedwith 66 (P = 00038) in thosepatients not taking part in the study
CONCLUSIONS
We found a prevalence of monogenicdiabetes in patients diagnosed20 yearsof age of 25 (95 CI 16ndash39) bysystematic testing using islet autoanti-bodies C-peptide and targeted next-generation sequencing of all monogenicdiabetes genes Using our approach ofscreening childrenadolescents withdiabetes using C-peptide followed byGAD and IA2 autoantibodies would iden-tify a subpopulation of 10 in whichgenetic testing will have a pick up rate of1 in 4 Using the online probability cal-culator (httpwwwdiabetesgenesorgcontentmody-probability-calculator)could further aid in the identification ofthose individuals who were most likelyto have MODY because in our study18 of 20 patients with monogenic dia-betes were shown to have a 1 in 13chance (or755) post-test probabilityof having MODY
The 25 (95 CI 16ndash39) preva-lence of monogenic diabetes we identi-fied is similar to the prevalence found inthree other large systematic populationstudies (12719) two from predomi-nantly European white populations (Po-land 31ndash42 Norway 11) and onefrom a multiethnic population fromthe US (14) (Table 1) The Polishstudy (7) used targeted case findingspredominantly using clinical criteriasupported by the lack of autoantibodiesand measurable C-peptide levels TheNorwegian population-based study (2)predominantly used antibody negativitycombined with a parental history of
Figure 2mdashPatient progression through pathway
1884 UK Screening for Pediatric Monogenic Diabetes Diabetes Care Volume 39 November 2016
Table
2mdashCharacte
risticsofth
e20patie
nts
identifi
edwith
monogenic
diabetes
StudyID
Gen
eMutatio
n
Protein
effectGen
der
Age
atdiagn
osis
(years)
Diab
etesduratio
n(years)
Initial
treatmen
tCurren
ttreatm
ent
BMI
percen
tileAffectedparen
t
UCPCR
(nmol
mmol)
GAD
IA2
Notes
211GCK
c97_117dup
p(V
al33_Lys39dup)
M3
13Insulin
None
99thMother
357NA
NA
KnownMODY
537GCK
c683CT
p(Th
r228Met)
M11
2Diet
None
NA
Mother
194NA
NA
KnownMODY
Siblin
gof538
538GCK
c683CT
p(Th
r228Met)
M9
1Diet
None
NA
Mother
173NA
NA
KnownMODY
Siblin
gof537
543GCK
c184GA
p(V
al62Met)
M4
02Diet
None
NA
Mother
NA
NA
NA
KnownMODY
Siblin
gof544
544GCK
c184GA
p(V
al62Met)
M3
2Diet
None
NA
Mother
NA
NA
NA
KnownMODY
Siblin
gof543
1396GCK
c1209del
p(Ile404fs)
M14
03Diet
None
71stMother
NA
NA
NA
KnownMODY
8002095GCK
c1019GT
p(Ser340Ile)
M9
5Diet
None
88thFath
er079
Neg
NA
KnownMODY
8002372GCK
c1340GA
p(A
rg447Gln)
M18
06Diet
None
90thNeith
erNottested
Neg
Nottested
New
lyiden
tified
MODY
599HNF1A
c608GA
p(A
rg203His)
F14
05OHA
OHA
99thBoth
paren
ts308
Neg
Neg
KnownMODY
1012HNF1A
c872del
p(Pro
291fs)F
1007
Diet
Diet
99thMother
56Neg
Neg
KnownMODY
Siblin
gof395
395HNF1A
c872del
p(Pro
291fs)F
1401
OHA
OHA
95thMother
58Neg
Neg
KnownMODY
Siblin
gof1012
455HNF1A
c872dup
p(G
ly292fs)F
123
OHA
OHA
57thFath
er086
Neg
Neg
KnownMODY
567HNF1A
c872dup
p(G
ly292fs)M
82
Diet
OHA
94thMother
173Neg
Neg
KnownMODY
686HNF4A
c749TC
p(Leu
250Pro)
M16
07Diet
Diet
99thFath
er474
NA
NA
KnownMODY
1348HNF4A
c340CT
p(A
rg114Trp)
F15
02Insulin
OHA
86thFath
er300
Neg
Neg
New
lyiden
tified
MODY
1203HNF4A
c340CT
p(A
rg114Trp)
M7
2Insulin
Insulin
39thNeith
er021
Neg
Neg
Duald
iagnosis
new
lyiden
tified
HNF4A
knowntyp
e1diab
etes
377HNF4A
c-12GA
p()
F11
2Insulin
Insulin
99thMother
028Neg
Neg
New
lyiden
tified
MODY
854HNF1B
c1-_151+d
elp(0)
(whole
genedeletio
n)
M11
2Insulin
Insulin
9thFath
er071
Neg
Neg
New
lyiden
tified
MODY
555ABCC8
c4139GA
p(A
rg1380His)
F11
8OHA
OHA
4thFath
er300
Neg
Neg
KnownMODY
758INSR
c3706CG
p(P
ro1236A
la)F
123
OHA
Diet
55thMother
907NA
NA
KnownMODY
Ffemale
IDid
entifi
cationMm
aleNAn
otapplicab
legenetic
diagn
osis
mad
eprio
rto
studyNegn
egativeOHAo
ralhypoglycem
icagen
tG
ADnegativede
finedinthis
studyas
99th
percentilebutGAD259
(975thpercentile)M
utations
aredescribed
usingthe
Hum
anGenom
eVariation
Societynom
enclatureguidelines
according
tothe
following
referencesequ
encesG
CKNM_0001623H
NF1A
NM_0005456H
NF4A
NM_1759144A
BCC8
NM_0012871741IN
SRNM_0002082D
iabetes
duratio
nat
timeofstu
dy
carediabetesjournalsorg Shepherd and Associates 1885
diabetes or lack of insulin therapy andHbA1c levels of 75 (58 mmolmol)The lower prevalence (11) probably re-flected that they studied children 0ndash14years of age rather than 0ndash20 years ofage (mean age at diagnosis in our study106 years) and only 10 patients weretested for GCK The US study (119) likeour study used systematic biomarkerscreening with genetic testing performedin all patients who had measurableC-peptide levels and did not have GADand IA2 autoantibodies The lower preva-lence in their cohort probably results fromnon-MODY patients having more ldquotype2 featuresrdquo suggesting a greater propor-tion of patients with young-onset type 2diabetes because the combined preva-lence of MODY in minority individuals wasvery similar to the prevalence of MODY innon-Hispanic white individuals (1) Therearemany other less comprehensive studies(252730) of the prevalence of monogenicdiabetes (Table 1) these are limited bystudying a single clinic using a nonsystem-atic assessment andor not making arobust molecular genetic diagnosis (con-firmed mutations not polymorphisms)Our study indicated a higher propor-
tion of known cases of MODY versusnew cases identified through systematicscreening The 28 patients with previ-ously confirmed MODY (15 who tookpart and 13 who did not take part inthe study) reflect the high levels ofawareness of monogenic diabetes inthese geographical regions The 13 pa-tients previously identified who did nottake part in the study included 9 withGCK MODY (who had been dischargedfrom clinic follow-up) 3 with HNF1AMODY and 1 with Wolfram syndromeThis study shows that clinical recognitionof key phenotypes in patients and theirfamily members can identify the major-ity of pediatric patients (15 of 20 inthis study) However the five new pa-tients identified through this pathwayof screening indicate the need for a sys-tematic approach If this approach wereused in other areas where the recogni-tion of monogenic diabetes is not so ap-parent then a greater proportion of newcases would be identified We havebased our prevalence figures only onthe population recruited in this studyhowever if the 13 patients who did nottake part were taken into account thiscould give a prevalence as high as 33(33 of 1016 patients) There are estimated
to be35000 children and young peoplewith diabetes who are under 19 yearsof age in the UK (3132) If the preva-lence of 25 found in those patientswho took part in this six-clinic surveyreflects the whole of the UK then thissuggests at least 875 expected patientswith MODY in this age group (95CI 560ndash1365) of whom 468 havereceived a diagnosis to date with50 still likely to be misdiagnosedas having type 1 diabetes
This approach of systematic testingcombined with clinical criteria can resultin a diagnosis in 99 of patients andthis is an advantage of this approach be-yond the recognition of monogenic diabe-tes We were able to use C-peptideautoantibody and genetic testing togive a clear diagnosis in 923 of patientsClinical criteria suggest that 33 hadtype 2 diabetes a figure that is very similarto the number of individuals with mono-genic diabetes as seen in other Europeanpopulations (72433) A total of 02 hadsecondary diabetes due to cystic fibrosiswhich probably reflects an underestimateasmanyof these patientswill not attend apediatric diabetes clinic A further 32were within 3 years of having received adiagnosis and probably had antibody-negative type 1 diabetes in the honey-moonperiod There remainedfivepatients(06) who were atypical and hard toclassifydthey may represent atypicaltype 1 diabetes (antibody negative andsignificant C-peptide levels3 years afterdiagnosis) or a presently unrecognizedsubtype of monogenic diabetes
There were limitations to this studyThe geographical areas where the studywas undertaken already had a highawareness of MODY so the number ofnew cases was low (25) relative tothose already known (75) while else-where in the UK we estimate that thisfigure is50 detected and 50 unde-tected We subjected only those pa-tients who had significant endogenousinsulin (C-peptide) levels and did nothave autoantibodies to systematic genetictesting although previous research(141718) and our failure to find anymu-tations in 65 patients who did have sig-nificant C-peptide levels but wereantibody positive support the idea thatthis approach wouldmiss very few casesUCPCR calculation was performed irre-spective of the duration of diabetesand it is acknowledged that some of
the patients tested close to receiving adiagnosis could be producing endoge-nous insulin during the honeymoon pe-riod and if retested over time thatthose patients with type 1 diabeteswould be expected to have decliningC-peptide levels The calculation of UCPCRis best for excluding patients 3 yearsafter diabetes is diagnosed while au-toantibody testing is best for excludingpatients close to diagnosis In thisstudy we wanted to test everyone re-gardless of disease duration so a test-ing method that used both biomarkersworked well If a study was performed ofpurely incident cases which would havean advantage of making the correct di-agnosis early then measuring C-peptidelevels would have little value and furthertesting could be performed on those in-dividuals who had negative results fromtesting for multiple autoantibodies Al-though patients were asked to send aldquopostmealrdquo urine sample the prandialstate of the patient was assumed (andnot observed) therefore we cannot becertain that all UCPCR tests were stimu-lated Our population consisted predomi-nantly (96) of whites and systematicstudies in other especially high-prevalencepopulations are also needed
There aremany strengths of this studyThe result is likely to be representative ofthe clinics studied because 795 of theeligible population took part a result thatshows the high acceptability of this ap-proach in pediatric clinics The systematicbiomarkerndashbased approach that is inde-pendent of clinical features allows atypi-cal patients to be detected (eg thosewith no family history of diabetes) Thisis the first study that has used next-generation sequencing to assess allknown causes of monogenic diabetes al-though themajority of patients (85) hadthe most common types of MODY (GCKHNF1A and HNF4A) so studies that havenot used this approach will have missedonly a few patients
This systematic high-uptake studygives a prevalence of 25 (95 CI 16ndash39) for monogenic diabetes in the UKpediatric population Patients with mono-genic diabetes were identified in everypediatric clinic The successful identifica-tion of patients with monogenic diabe-tes is crucial because they requiredifferent treatment than those withtype 1 or type 2 diabetes The vast major-ity (99) of pediatric patients can be
1886 UK Screening for Pediatric Monogenic Diabetes Diabetes Care Volume 39 November 2016
successfully classified by UCPCR antibodytesting genetic testing and clinical crite-ria UCPCR is a noninvasive and inexpen-sive test which could be more widelyused in the pediatric age group whereit has a high acceptability This screeningalgorithm is a practical approach to de-termining the prevalence of cases in aclinic to ensure the correct diagnosis ofsubtypes of diabetes Confirming a prev-alence of MODY of 25 in the pediatricpopulation indicates that all those in-volved in pediatric diabetes care shouldbe aware of the possibility of an alterna-tive diagnosis and know how to referpatients for genetic testing
Acknowledgments The authors thank the pa-tientswhotookpartinthisstudyandthenurseswhorecruited them for their support with this projectFunding This work presents independent re-search commissioned by the Health InnovationChallenge Fund a parallel funding partnershipbetween theWellcome Trust and the DepartmentofHealth(grantHICF-1009-041)andwassupportedbytheNational Institute forHealthResearch (NIHR)ExeterClinicalResearchFacility and theSouthWestPeninsula Diabetes Research Network MS issupported by the NIHR Exeter Clinical ResearchFacilityTJM is fundedbyanNIHRCSOFellowshipSE and ATH are both Wellcome Trust SeniorInvestigators ERP is a Wellcome Trust New In-vestigator ATH is an NIHR Senior InvestigatorTheviewsexpressed in thispublicationare those
of the authors and not necessarily those of theWellcomeTrust theNHS theNational Institute forHealth Research or the Department of HealthDuality of Interest No potential conflicts ofinterest relevant to this article were reportedAuthor Contributions MS wrote the manu-script and collected and analyzed the data BSanalyzed the data and reviewed and editedthe manuscript SH collected the data andreviewed the manuscript MH coordinatedthe project assistedwith the data and reviewedthe manuscript TJM coordinated the urinaryC-peptide creatinine ratio determination andantibody testing and reviewed the manuscriptKC assistedwith genetic data and reviewed andedited themanuscript RAO contributed to thediscussion and reviewed the manuscript BKdeveloped the protocol submitted the ethicsapplication and reviewed the manuscript CHreviewed the manuscript JC KM CM RSBF SR andSG facilitatedpatient recruitmentwithin their pediatric clinics and reviewed themanuscript SE coordinated the genetic testingand reviewed the manuscript ERP coordi-nated the Tayside arm of the project and re-viewed and edited the manuscript ATHdesigned the study contributed to the discus-sion and reviewed and edited the manuscriptThe UNITED team collected the data MS is theguarantor of this work and as such had fullaccess to all the data in the study and takesresponsibility for the integrity of the data andthe accuracy of the data analysis
References1 Pihoker C Gilliam LK Ellard S et al SEARCHfor Diabetes in Youth Study Group Preva-lence characteristics and clinical diagnosis ofmaturity onset diabetes of the young due to mu-tations inHNF1A HNF4A and glucokinase resultsfrom the SEARCH for Diabetes in Youth J ClinEndocrinol Metab 2013984055ndash40622 Irgens HU Molnes J Johansson BB et al Prev-alence of monogenic diabetes in the population-based Norwegian Childhood Diabetes RegistryDiabetologia 2013561512ndash15193 Carmody D Lindauer KL Naylor RN Adoles-cent non-adherence reveals a genetic cause fordiabetes Diabet Med 201532e20ndashe234 Gandica RG Chung WK Deng L Goland RGallagher MP Identifying monogenic diabetesin a pediatric cohort with presumed type 1 di-abetes Pediatr Diabetes 201516227ndash2335 Lambert AP Ellard S Allen LI et al Identify-ing hepatic nuclear factor 1alpha mutations inchildren and young adults with a clinical diag-nosis of type 1 diabetes Diabetes Care 200326333ndash3376 Thirumalai A Holing E Brown Z Gilliam LK Acase of hepatocyte nuclear factor-1b (TCF2) ma-turity onset diabetes of the youngmisdiagnosedas type 1 diabetes and treated unnecessarilywith insulin J Diabetes 20135462ndash4647 Fendler W Borowiec M Baranowska-Jazwiecka A et al Prevalence of monogenicdiabetes amongst Polish children after a nation-wide genetic screening campaign Diabetologia2012552631ndash26358 Rubio-Cabezas O Edghill EL Argente JHattersley AT Testing for monogenic diabetesamong children and adolescents with antibody-negative clinically defined type 1 diabetes Dia-bet Med 2009261070ndash10749 Murphy R Ellard S Hattersley AT Clinicalimplications of a molecular genetic classifica-tion of monogenic beta-cell diabetes Nat ClinPract Endocrinol Metab 20084200ndash21310 Rubio-Cabezas O Hattersley AT NjoslashlstadPR et al International Society for Pediatricand Adolescent Diabetes ISPAD Clinical PracticeConsensus Guidelines 2014 The diagnosis andmanagement of monogenic diabetes in childrenand adolescents Pediatr Diabetes 201415(Suppl 20)47ndash6411 Craig ME Jefferies C Dabelea D Balde NSeth A Donaghue KC International Societyfor Pediatric and Adolescent Diabetes ISPADClinical Practice Consensus Guidelines 2014Definition epidemiology and classification ofdiabetes in children and adolescents PediatrDiabetes 201415(Suppl 20)4ndash1712 Colclough K Saint-Martin C Timsit J EllardS Bellanne-Chantelot C Clinical utility gene cardfor maturity-onset diabetes of the young Eur JHum Genet 12 February 2014 [Epub ahead ofprint] DOI 101038ejhg20141413 Shields BM Hicks S Shepherd MHColclough K Hattersley AT Ellard S Maturity-onset diabetes of the young (MODY) howmanycases are we missing Diabetologia 2010532504ndash250814 Besser RE Shepherd MH McDonald TJet al Urinary C-peptide creatinine ratio is apractical outpatient tool for identifying hepato-cyte nuclear factor 1-alphahepatocyte nuclearfactor 4-alpha maturity-onset diabetes of the
young from long-duration type 1 diabetes Di-abetes Care 201134286ndash29115 McDonald TJ Knight BA Shields BMBowman P Salzmann MB Hattersley AT Stabil-ity and reproducibility of a single-sample urinaryC-peptidecreatinine ratio and its correlation with24-h urinary C-peptide Clin Chem 2009552035ndash203916 Besser RE Ludvigsson J Jones AG et alUrine C-peptide creatinine ratio is a noninvasivealternative to the mixed-meal tolerance test inchildren and adults with type 1 diabetes Diabe-tes Care 201134607ndash60917 Besser RE Shields BM Hammersley SEet al Home urine C-peptide creatinine ratio(UCPCR) testing can identify type 2 and MODYin pediatric diabetes Pediatr Diabetes 201314181ndash18818 McDonald TJ Colclough K Brown R et alIslet autoantibodies can discriminate maturity-onset diabetes of the young (MODY) from type 1diabetes Diabet Med 2011281028ndash103319 Kanakatti Shankar R Pihoker C Dolan LMet al SEARCH for Diabetes in Youth Study GroupPermanent neonatal diabetes mellitus preva-lence and genetic diagnosis in the SEARCH for Di-abetes in Youth Study Pediatr Diabetes 201314174ndash18020 Hameed S Ellard S Woodhead HJ et alPersistently autoantibody negative (PAN)type 1 diabetes mellitus in children Pediatr Di-abetes 201112142ndash14921 Wheeler BJ Patterson N Love DR et alFrequency and genetic spectrum of maturity-onset diabetes of the young (MODY) in southernNew Zealand J Diabetes Metab Disord 2013124622 Redondo MJ Rodriguez LM Escalante MSmith EO Balasubramanyam A HaymondMW Types of pediatric diabetes mellitus de-fined by anti-islet autoimmunity and randomC-peptide at diagnosis Pediatr Diabetes 201314333ndash34023 Ehtisham S Hattersley AT Dunger DBBarrett TG British Society for Paediatric Endo-crinology and Diabetes Clinical Trials GroupFirst UK survey of paediatric type 2 diabetesand MODY Arch Dis Child 200489526ndash52924 Neu A Feldhahn L Ehehalt S Hub R RankeMB DIARY group Baden-Wurttemberg Type2 diabetes mellitus in children and adolescentsis still a rare disease in Germany a population-based assessment of the prevalence of type 2diabetes and MODY in patients aged 0-20 yearsPediatr Diabetes 200910468ndash47325 Amed S Dean HJ Panagiotopoulos C et alType 2 diabetes medication-induced diabetesand monogenic diabetes in Canadian children aprospective national surveillance study Diabe-tes Care 201033786ndash79126 Galler A Stange T Muller G et al Child-hood Diabetes Registry in Saxony Germany In-cidence of childhood diabetes in children agedless than 15 years and its clinical and metaboliccharacteristics at the time of diagnosis datafrom the Childhood Diabetes Registry of Sax-ony Germany Horm Res Paediatr 201074285ndash29127 Schober E Rami B Grabert M et al DPV-Wiss Initiative of the GermanWorking Group forPaediatric Diabetology and Phenotypical as-pects of maturity-onset diabetes of the young
carediabetesjournalsorg Shepherd and Associates 1887
(MODY diabetes) in comparison with type 2 di-abetes mellitus (T2DM) in children and adoles-cents experience from a large multicentredatabase Diabet Med 200926466ndash47328 Freeman JV Cole TJ Chinn S et al Crosssectional stature and weight reference curvesfor the UK 1990 Arch Dis Child 19957317ndash2429 Ellard S Lango Allen H De Franco E et alImproved genetic testing for monogenic diabe-tes using targeted next-generation sequencingDiabetologia 2013561958ndash196330 Awa WL Thon A Raile K et al DPV-WissStudy Group Genetic and clinical characteristicsof patients with HNF1A gene variations from the
German-Austrian DPV database Eur J Endocri-nol 2011164513ndash52031 Health amp Social Care Information CentreNational diabetes audit 2011-12 report 1 careprocesses and treatment targets CCG and LHGdata tables [Internet] 2013 Available fromhttpwwwhscicgovuksearchcatalogueproductid=13129ampq=22National+diabetes+audit22ampsort=Relevanceampsize=10amppage=1top Ac-cessed 3 January 201632 Diabetes in Scotland Scottish Diabetes Sur-vey 2014 [Internet] 2014 Available from httpwwwdiabetesinscotlandorgukPublicationsSDS2014pdf Accessed 3 January 2016
33 Vaziri-Sani F Delli AJ Elding-Larsson Het al A novel triple mix radiobinding assay forthe three ZnT8 (ZnT8-RWQ) autoantibody vari-ants in children with newly diagnosed diabetesJ Immunol Methods 201137125ndash3734 Yorifuji T Fujimaru R Hosokawa Y et alComprehensive molecular analysis of Japa-nese patients with pediatric-onset MODY-type diabetes mellitus Pediatr Diabetes20121326ndash3235 Chambers C Fouts A Dong F et al Charac-teristics of maturity onset diabetes of the youngin a large diabetes center Pediatr Diabetes201617360ndash367
1888 UK Screening for Pediatric Monogenic Diabetes Diabetes Care Volume 39 November 2016
Monogenic diabetes is often not recog-nized in children or adolescents andmisdiagnosis as type 1 in these individ-uals is common (1ndash8) Making the cor-rect diagnosis of monogenic diabetes isvitally important because the manage-ment of the most common subtypes(GCK HNF1A and HNF4A maturity-onsetdiabetes of the young [MODY]) is mark-edly different from that for type 1 diabe-tes (910) Molecular diagnosis improvesclinical care by confirming the diagnosisaiding prediction of the expected clinicalcourse of the disease and guiding appro-priatemanagement and family follow-up(10ndash12) Because of the predominanceof type 1 diabetes in children the poten-tial significance of a parent with diabetesor possible noninsulin dependence maybe overlooked This leads to unnecessaryinsulin treatment with a mean delayfrom diabetes diagnosis to the correct ge-netic diagnosis of 93 years (K ColcloughS Ellard unpublished observations)(based on 1240 patients who were ini-tially diagnosed with diabetes20 yearsof age but subsequently received a ge-netic diagnosis of GCK HNF1A or HNF4AMODY)The present approach to diagnosing
monogenic diabetes requires clinicalrecognition by an alert health care pro-fessional and subsequent genetic testingBecause genetic testing for monogenicdiabetes is now widely available world-wide the major barrier is clinician recog-nition (although costs and lack of medicalinsurance coverage of genetic testingcan also limit who is tested) Despitethe availability of guidelines advisingwhen a diagnosis of monogenic diabe-tes in children should be suspected (10)genetic testing is under-requested Wehave shown that the underdiagnosis ofMODY in some regions in the UK re-flects reduced testing rather than inap-propriate testing (13)Biomarker tests can help to identify
appropriate candidates for genetic test-ing for monogenic diabetes avoidingreliance on clinical recognition Thesebiomarkers are most useful in enabling afirm diagnosis of type 1 diabetes to bemade obviating the consideration of ge-netic testing The lack of significant en-dogenous insulin production (stimulatedserum C-peptide level 200 pmolL) isseen in type 1 diabetes outside the honey-moon period Urinary C-peptide creatinineratio (UCPCR) provides a simple stable
reliable noninvasive measure which canbe tested on a sample posted from homedirect to a laboratory (1415) and hasbeen validated against the mixed-mealtolerancetest (16)AUCPCR$02nmolmolindicates the presence of endogenousinsulin and has been used to differenti-ate patients with MODY from those withtype 1 diabetes5 years after diagnosis(17) Islet autoantibodies are found inthe majority of patients with type 1 di-abetes especially when measured closeto diagnosis and are an excellent discrim-inator between type 1 diabetes andMODY (18)
A large number of studies have triedto assess the prevalence of monogenicdiabetes in the pediatric population(Table 1) however the majority ofthese studies did not use a systematicapproach or were limited to single clinicpopulations A further limitation is thatno studies to date have investigated allthe causes of monogenic diabetes (Table1) Only three studies have systematicallyscreened large populations as follows1) a US multicenter systematic study(SEARCH) identified a minimum preva-lence of 12 with MODY (1) and a fur-ther 02 with neonatal diabetes (19)2) a Norwegian nationwide study identi-fied a minimum prevalence of mono-genic diabetes in children of 11 (2)and 3) a Polish study identified a mini-mum prevalence of 31ndash42 (7) Othersmaller studies (4820ndash22) report screen-ing or assessment of single pediatric clinicpopulations and although islet autoanti-body negativity is often used to identifychildren who could benefit from genetictesting the screening and testing strate-gies are variable with estimates of prev-alence up to 25 Surveyquestionnaireor epidemiological data relying on physi-cian reporting and recognition of the clin-ical features of monogenic diabetes inpediatric populations statewidely varyingprevalences of 06ndash42 (723ndash27) How-ever these approaches do not involvesystematic screening and thereforemay be considered less accurate
We report the first prevalence studyof monogenic diabetes in the UK pedi-atric population using a systematicscreening algorithm and genetic testingfor all subtypes of monogenic diabetes
The aim of this study was to identifythe prevalence of monogenic diabetesin the UK pediatric diabetes populationby systematic screening
RESEARCH DESIGN AND METHODS
Study EligibilityAll patients with diabetes who were20 years of age attending one of sixpediatrictransition clinics across SouthWest England and Tayside Scotlandwere eligible to take part Ethical ap-proval was granted by the National Re-search Ethics Service Committee SouthWestndashCentral Bristol Participants under16 years of age were asked to provide as-sent and their parents provided consent
The total number of potential recruits(n = 1016) was ascertained by the localpediatric clinical teams from their clinicrecords (ie all their patients with dia-betes who were 20 years of age wereidentified 779 in South West Englandand 237 in Tayside) Informed consentwas obtained by a member of the re-search team prior to data collectionand participants $16 years of agewere asked to provide consent them-selves and if they lacked capacity theirparents were asked to provide consentTime from diagnosis was not an exclu-sion criterion Data collection includedthe following sex ethnic group currentageage at diagnosis initialcurrenttreatment time to insulin treatmentfamily history of diabetes most recenthighest HbA1c level heightweight at di-agnosis and time of recruitment and thepresence of learning difficulties or deaf-ness BMI was reported as age-adjustedpercentiles to enable comparison acrossage groups (28)
Screening MethodThe study comprised three potentialstages that systematically identifiedthose patients who were eligible for ge-netic testing (Fig 1)
Stage 1 consisted of a urine sample forthe measurement of UCPCR (14ndash16) Par-ticipants receiving insulin treatment wereasked to mail a urine sample collected 2 hafter the largest meal of the day that con-tained carbohydrate to a single laboratoryat the Royal Devon and Exeter NHS Foun-dation Trust Participants with endoge-nous insulin production ascertained byUCPCR of $02 nmolmmol and thosenot receiving insulin treatment progressedto stage 2 of the study Patients with aUCPCR02 nmolmmol indicating insu-lin deficiency were considered to have adiagnosis of type 1 diabetes (1416)
Stage 2 comprised a blood samplethat tested for the presence of islet
1880 UK Screening for Pediatric Monogenic Diabetes Diabetes Care Volume 39 November 2016
Table
1mdashAppro
ach
esuse
dto
identify
monogenic
diabetesin
pediatric
populations
Typeofstudy
Country
Area
Initialcohort(n)
Cohortcharacteristics
Testingstrategy
(subgrouptested
)Gen
estested
Prevalen
cein
genetically
tested
Minim
alprevalence
of
monogenic
diabetes
Reference
System
aticstudiesordered
bynumber
instudy
Multicen
terpopulation
based
US
6centers
California
OhioH
awaii
South
Carolina
Washington
596
31)
Diagn
osed20
years
1)AB-ve(3
2)fasting
C-pep
tide$08ngmL
(n=58
6)
1)HNF1AH
NF4A
GCK
1)84(47586
)12
1
2)Diagnosed6months
2)Diagn
osed6months
(n=7)
2)KC
NJ11
INS
ABCC8
2)71
4(57)
02
(total14)
19
Nationwidepopulation
based
Norw
ayNationwide
275
6New
lydiagnosed
age0ndash14
years
1)AB-ve(3
2)and
affected
paren
t(n
=46
)1)
HNF1AH
NF4A
MIDD
1)13
0(646)
11
2
2)AB-veHbA1c75
(58mmolmol)and
notreceivinginsulin
(n=10
)
2)GCK
2)30
0(310)
3)Diagn
osed12
months
(n=24
)3)
KCNJ11
ABCC8
INS
3)16
6(424)
Epidem
iologicald
ata
nationwidegenetictest
results
Poland
3centers
Lodz
Katowice
Gdan
sk
256
8Age
0ndash18
years
1)AB-ve
affected
paren
tnoninsulin
dep
enden
t1)
HNF1AH
NF4A
HNF1B
321(100
311)
31ndash42
7
2)HbA1c75
(58mmolmol)
2)GCK
3)Diagn
osed6months
3)KC
NJ11
ABCC8
INS
4)Syndromicdiabetes
4)WFSAlstrom
Singleped
iatricclinic
population
US
New
York
939
ClinicaldiagnosisT1D
AB-ve(3
3)pluseither
GCK
86
(558)
05
4
Age
6monthsto
20years
HbA1c7
(53mmolmol)and05
unitsinsulinkgday
1year
postdiagnosis
C-pep
tidepositive
or
3genFH(n
=58
)
HNF1A
Pediatricclinicsin
single
city
Australia
Sydney
497
1)Clinicaldiagn
osisT1D
AB-ve(3
4on
2occasion
s)(n
=19
)1)
HNF1AH
NF4A
2)INSKC
NJ11
5(119)
12
20
2)Diagnosed6monthsto
16years
Singleped
iatricclinic
population
Spain
Madrid
252
1)Clinicaldiagn
osisT1D
AB-ve(3
5)(n
=25
)1)
HNF1AH
NF4A
80
(225)
08
8
2)Diagnosed6monthsto
17years
2)KC
NJ11INS
Pediatriccliniccase
histories
New
Zealand
South
Island
160
Pediatricdiabetes
18
years
AB-ve(3
2)(n
=4)
GCK
HNF1B
HNF1A
25(4160
)25
21
Con
tinu
edon
p18
82
carediabetesjournalsorg Shepherd and Associates 1881
1882 UK Screening for Pediatric Monogenic Diabetes Diabetes Care Volume 39 November 2016
autoantibodies (GAD and IA2) to identifythose with autoimmune diabetes Thistest was performed in all participantswith significant endogenous insulin levels(either a UCPCR $02 nmolmmol whilereceiving insulin treatment or not receiv-ing insulin treatment) If islet autoantibodyresults were available from previous test-ing these were used otherwise a bloodsample was taken for antibody testingPatients with GAD or IA2 levels 99thpercentile were deemed islet autoanti-body positive (18) and were consideredto have a diagnosis of type 1 diabetesStage 3 consisted of genetic testing in
participants who were UCPCR positiveand islet autoantibody negative DNAwas extracted using standard methodsfrom a blood sample that was usuallyobtained at the same time as the samplefor islet autoantibody testing Sanger se-quencing analysis of the HNF1A andHNF4A genes and dosage analysis bymultiplex ligation-dependent probe am-plification to detect partial and wholegene deletions of HNF1A HNF4A GCKand HNF1B was undertaken for all pa-tients with additional Sanger sequenc-ing analysis of the GCK gene undertakenfor patients with maximum HbA1c levelsof76 (60 mmolmol) This testingstrategywas performed initially becausethese are the most common genes im-plicated in MODY accounting for95of all MODY cases in the UK (13) andare amenable to treatment change Pa-tients with no pathogenic mutationidentified by Sanger sequencing andmultiplex ligation-dependent probe am-plification then underwent targetednext-generation sequencing to look for
mutations in 29 genes known to causemonogenicdiabetes and themitochondrialmutation m3243AG causing maternallyinherited diabetes and deafness using theassay published by Ellard et al (29)
Statistical AnalysisData were double entered onto a data-base and subsequently cleaned Dataarepresented as proportions andmedian(interquartile range [IQR]) where appro-priate because of the non-normality ofdata Prevalence was calculated as theproportion of patients with monogenicdiabetes out of the total number of pa-tients studied Data were analyzed usingStata version 131
RESULTS
A total of 795 of the eligible popula-tion (n = 808 of 1016) completed thestudy (Fig 2) Fifteen of these partici-pants had previously undergone genetictesting and were already known to havemonogenic diabetes (Table 2)
Patient CharacteristicsA total of 54 of participants were male(441 male 376 female) The median ageat study recruitment was 13 years (IQR =10 16) the median age at diagnosis was8 years (IQR = 4 11) and all individualsreceived a diagnosis of diabetes at6 months of age The median durationof diabeteswas 43 years (IQR = 16 79)The majority (788 participants [96]) ofthe cohort were white reflecting thepopulation demographics in these areasA total of 792 patients (97) were receiv-ing insulin treatment at the time of studyrecruitment including 4 patients whowere receiving treatment with insulin in
addition to metformin Twenty-five pa-tients (3) were noninsulin treated with11 patients receiving oral agents onlyand 14 were being treated withdiet alone The median HbA1c level was86 (IQR = 77 97 [70 mmolmol IQR =61 83]) and the median BMI percentilewas 79 (IQR = 56 94)
Stage 1 UCPCRA total of 547 of 817 patients (67)wereUCPCR negative (02 nmolmol) indi-cating insulin deficiency and weretherefore considered to have type 1 di-abetes and these individuals did notundergo further testing In addition261 patients (32) had significant endoge-nous insulin production ($02 nmolmol)this included 236 patients who weretreated with insulin and 25 patientswho were not treated with insulin
Stage 2 AntibodiesThe 253 patients with significant endog-enous insulin levels underwent isletautoantibody testing which included236 patients who were treated with in-sulin and confirmed to be UCPCR posi-tive through stage 1 of the study and17 patients who were not treated withinsulin Eight of 15 patients who hadpreviously received a diagnosis ofmonogenic diabetes did not undergo an-tibody testing (but none of these weretreated with insulin) and 9 patients didnot return their blood sample for anti-body testing
A total of 179 of 253 participants wereislet autoantibody positive confirming adiagnosis of type 1 diabetes Forty-fiveof these participants were positive toboth GAD and IA2 28 were positive toGAD only 21 were positive to GAD butIA2 was not tested for and 85 were pos-itive to IA2 only indicating the impor-tance of testing for both autoantibodiesThe 74 participants who were antibodynegative continued to stage 3 for genetictesting
Stage 3 Genetic TestingThe prevalence of monogenic diabetesin this UK pediatric diabetes popula-tion that was 20 years of age was25 (95 CI 15ndash39) A total of82 of 808 patients (101) had under-gone genetic testing and 20 of these(24 1 in 4 patients) had monogenicdiabetes (Table 2) Fifteen of 20 patientswere previously known to have mono-genic diabetes (7 GCK MODY 5 HNF1A
Figure 1mdashPathway of testing
carediabetesjournalsorg Shepherd and Associates 1883
MODY 1 HNF4AMODY 1 ABCC8MODYand 1 patientwith typeA insulin resistancedue to a heterozygous INSRmutation) and5 new cases of monogenic diabetes(3 HNF4A MODY 1 HNF1B MODY 1 GCKMODY) were identified during the studyOne of these patients had a dual diagno-sis of HNF4A MODY (heterozygous forthe pArg114Trp mutation) and type 1diabetes (GAD negative as defined inthis study as the 99th percentile andtherefore proceeded to genetic testingbut with a GAD titer of 259975th per-centile and a UCPCR of 021 nmolmol2 years after diagnosis and had receivedcontinuous insulin treatment from thetime of diagnosis) Patients with mono-genic diabetes were found in all six clin-ics with a prevalence varying between12 and 37To assess whether we had missed
cases of monogenic diabetes in thosewith islet autoantibodies 65 of 179 pa-tients with positive autoantibodies un-derwent Sanger sequencing analysis ofthe most common MODY genes (GCKHNF1A and HNF4A) no mutations werefound
Characteristics of Patients Negativeon Genetic TestingDiagnosis was not established using thistesting pathway in 62 participants whowere UCPCR positive islet autoantibodynegative and negative for mutations in
29 genes known to cause monogenicdiabetes Secondary causes of diabeteswere known in two individuals with apreviously recorded diagnosis of cysticfibrosisndashrelated diabetes Twenty-sevenof 62 of these patients (33 of the co-hort) met the diagnostic criteria fortype 2 diabetes (no monogenic or sec-ondary cause BMI $85th percentileand antibody negative [httpwebispadorgsitesdefaultfilesresourcesfilesidf-ispad_diabetes_in_childhood_and_adolescence_guidelines_2011_0pdf]) but were not assessed for insulinresistance or other metabolic features
Uncertainty over the diagnosis re-mained in 33 individuals (4 of thewhole cohort) The most likely diagnosisin these individuals was islet autoanti-body-negative type 1 diabetes becausethey were close to diagnosis (medianduration 08 years [IQR = 04 28]) andwere not overweight (median BMI in the51st percentile [IQR = 43 67]) Twenty-six of 33 of these individuals had a di-abetes duration of 3 years and socould be considered to be within thehoneymoon phase repeating testingfor the UCPCR in these individuals overtime could prove to be useful However5 of 33 individuals had a median diabe-tes duration of 61 years (range 5ndash10years) median BMI in the 53rd percentile(range 46th to 81st percentile) with a
medianUCPCRof 036nmolmmol (range021ndash127 nmolmmol) therefore thediabetes in these individuals should beconsidered atypical and not fitting aclear diagnostic category
Only 194 of the eligible patientswithin these pediatric diabetes popula-tions (n = 198) did not take part in thisstudy This included 13 known patientswith monogenic diabetes (10 patientshad GCK MODY and were thereforenot under the care of a diabetes team3 patientswith HNF1A and 1 patientwithWolfram syndrome) Therefore this co-hort was not biased to include all thosepatients with known monogenic diabe-tes The prevalence of monogenic diabe-tes in those patients recruited was 25comparedwith 66 (P = 00038) in thosepatients not taking part in the study
CONCLUSIONS
We found a prevalence of monogenicdiabetes in patients diagnosed20 yearsof age of 25 (95 CI 16ndash39) bysystematic testing using islet autoanti-bodies C-peptide and targeted next-generation sequencing of all monogenicdiabetes genes Using our approach ofscreening childrenadolescents withdiabetes using C-peptide followed byGAD and IA2 autoantibodies would iden-tify a subpopulation of 10 in whichgenetic testing will have a pick up rate of1 in 4 Using the online probability cal-culator (httpwwwdiabetesgenesorgcontentmody-probability-calculator)could further aid in the identification ofthose individuals who were most likelyto have MODY because in our study18 of 20 patients with monogenic dia-betes were shown to have a 1 in 13chance (or755) post-test probabilityof having MODY
The 25 (95 CI 16ndash39) preva-lence of monogenic diabetes we identi-fied is similar to the prevalence found inthree other large systematic populationstudies (12719) two from predomi-nantly European white populations (Po-land 31ndash42 Norway 11) and onefrom a multiethnic population fromthe US (14) (Table 1) The Polishstudy (7) used targeted case findingspredominantly using clinical criteriasupported by the lack of autoantibodiesand measurable C-peptide levels TheNorwegian population-based study (2)predominantly used antibody negativitycombined with a parental history of
Figure 2mdashPatient progression through pathway
1884 UK Screening for Pediatric Monogenic Diabetes Diabetes Care Volume 39 November 2016
Table
2mdashCharacte
risticsofth
e20patie
nts
identifi
edwith
monogenic
diabetes
StudyID
Gen
eMutatio
n
Protein
effectGen
der
Age
atdiagn
osis
(years)
Diab
etesduratio
n(years)
Initial
treatmen
tCurren
ttreatm
ent
BMI
percen
tileAffectedparen
t
UCPCR
(nmol
mmol)
GAD
IA2
Notes
211GCK
c97_117dup
p(V
al33_Lys39dup)
M3
13Insulin
None
99thMother
357NA
NA
KnownMODY
537GCK
c683CT
p(Th
r228Met)
M11
2Diet
None
NA
Mother
194NA
NA
KnownMODY
Siblin
gof538
538GCK
c683CT
p(Th
r228Met)
M9
1Diet
None
NA
Mother
173NA
NA
KnownMODY
Siblin
gof537
543GCK
c184GA
p(V
al62Met)
M4
02Diet
None
NA
Mother
NA
NA
NA
KnownMODY
Siblin
gof544
544GCK
c184GA
p(V
al62Met)
M3
2Diet
None
NA
Mother
NA
NA
NA
KnownMODY
Siblin
gof543
1396GCK
c1209del
p(Ile404fs)
M14
03Diet
None
71stMother
NA
NA
NA
KnownMODY
8002095GCK
c1019GT
p(Ser340Ile)
M9
5Diet
None
88thFath
er079
Neg
NA
KnownMODY
8002372GCK
c1340GA
p(A
rg447Gln)
M18
06Diet
None
90thNeith
erNottested
Neg
Nottested
New
lyiden
tified
MODY
599HNF1A
c608GA
p(A
rg203His)
F14
05OHA
OHA
99thBoth
paren
ts308
Neg
Neg
KnownMODY
1012HNF1A
c872del
p(Pro
291fs)F
1007
Diet
Diet
99thMother
56Neg
Neg
KnownMODY
Siblin
gof395
395HNF1A
c872del
p(Pro
291fs)F
1401
OHA
OHA
95thMother
58Neg
Neg
KnownMODY
Siblin
gof1012
455HNF1A
c872dup
p(G
ly292fs)F
123
OHA
OHA
57thFath
er086
Neg
Neg
KnownMODY
567HNF1A
c872dup
p(G
ly292fs)M
82
Diet
OHA
94thMother
173Neg
Neg
KnownMODY
686HNF4A
c749TC
p(Leu
250Pro)
M16
07Diet
Diet
99thFath
er474
NA
NA
KnownMODY
1348HNF4A
c340CT
p(A
rg114Trp)
F15
02Insulin
OHA
86thFath
er300
Neg
Neg
New
lyiden
tified
MODY
1203HNF4A
c340CT
p(A
rg114Trp)
M7
2Insulin
Insulin
39thNeith
er021
Neg
Neg
Duald
iagnosis
new
lyiden
tified
HNF4A
knowntyp
e1diab
etes
377HNF4A
c-12GA
p()
F11
2Insulin
Insulin
99thMother
028Neg
Neg
New
lyiden
tified
MODY
854HNF1B
c1-_151+d
elp(0)
(whole
genedeletio
n)
M11
2Insulin
Insulin
9thFath
er071
Neg
Neg
New
lyiden
tified
MODY
555ABCC8
c4139GA
p(A
rg1380His)
F11
8OHA
OHA
4thFath
er300
Neg
Neg
KnownMODY
758INSR
c3706CG
p(P
ro1236A
la)F
123
OHA
Diet
55thMother
907NA
NA
KnownMODY
Ffemale
IDid
entifi
cationMm
aleNAn
otapplicab
legenetic
diagn
osis
mad
eprio
rto
studyNegn
egativeOHAo
ralhypoglycem
icagen
tG
ADnegativede
finedinthis
studyas
99th
percentilebutGAD259
(975thpercentile)M
utations
aredescribed
usingthe
Hum
anGenom
eVariation
Societynom
enclatureguidelines
according
tothe
following
referencesequ
encesG
CKNM_0001623H
NF1A
NM_0005456H
NF4A
NM_1759144A
BCC8
NM_0012871741IN
SRNM_0002082D
iabetes
duratio
nat
timeofstu
dy
carediabetesjournalsorg Shepherd and Associates 1885
diabetes or lack of insulin therapy andHbA1c levels of 75 (58 mmolmol)The lower prevalence (11) probably re-flected that they studied children 0ndash14years of age rather than 0ndash20 years ofage (mean age at diagnosis in our study106 years) and only 10 patients weretested for GCK The US study (119) likeour study used systematic biomarkerscreening with genetic testing performedin all patients who had measurableC-peptide levels and did not have GADand IA2 autoantibodies The lower preva-lence in their cohort probably results fromnon-MODY patients having more ldquotype2 featuresrdquo suggesting a greater propor-tion of patients with young-onset type 2diabetes because the combined preva-lence of MODY in minority individuals wasvery similar to the prevalence of MODY innon-Hispanic white individuals (1) Therearemany other less comprehensive studies(252730) of the prevalence of monogenicdiabetes (Table 1) these are limited bystudying a single clinic using a nonsystem-atic assessment andor not making arobust molecular genetic diagnosis (con-firmed mutations not polymorphisms)Our study indicated a higher propor-
tion of known cases of MODY versusnew cases identified through systematicscreening The 28 patients with previ-ously confirmed MODY (15 who tookpart and 13 who did not take part inthe study) reflect the high levels ofawareness of monogenic diabetes inthese geographical regions The 13 pa-tients previously identified who did nottake part in the study included 9 withGCK MODY (who had been dischargedfrom clinic follow-up) 3 with HNF1AMODY and 1 with Wolfram syndromeThis study shows that clinical recognitionof key phenotypes in patients and theirfamily members can identify the major-ity of pediatric patients (15 of 20 inthis study) However the five new pa-tients identified through this pathwayof screening indicate the need for a sys-tematic approach If this approach wereused in other areas where the recogni-tion of monogenic diabetes is not so ap-parent then a greater proportion of newcases would be identified We havebased our prevalence figures only onthe population recruited in this studyhowever if the 13 patients who did nottake part were taken into account thiscould give a prevalence as high as 33(33 of 1016 patients) There are estimated
to be35000 children and young peoplewith diabetes who are under 19 yearsof age in the UK (3132) If the preva-lence of 25 found in those patientswho took part in this six-clinic surveyreflects the whole of the UK then thissuggests at least 875 expected patientswith MODY in this age group (95CI 560ndash1365) of whom 468 havereceived a diagnosis to date with50 still likely to be misdiagnosedas having type 1 diabetes
This approach of systematic testingcombined with clinical criteria can resultin a diagnosis in 99 of patients andthis is an advantage of this approach be-yond the recognition of monogenic diabe-tes We were able to use C-peptideautoantibody and genetic testing togive a clear diagnosis in 923 of patientsClinical criteria suggest that 33 hadtype 2 diabetes a figure that is very similarto the number of individuals with mono-genic diabetes as seen in other Europeanpopulations (72433) A total of 02 hadsecondary diabetes due to cystic fibrosiswhich probably reflects an underestimateasmanyof these patientswill not attend apediatric diabetes clinic A further 32were within 3 years of having received adiagnosis and probably had antibody-negative type 1 diabetes in the honey-moonperiod There remainedfivepatients(06) who were atypical and hard toclassifydthey may represent atypicaltype 1 diabetes (antibody negative andsignificant C-peptide levels3 years afterdiagnosis) or a presently unrecognizedsubtype of monogenic diabetes
There were limitations to this studyThe geographical areas where the studywas undertaken already had a highawareness of MODY so the number ofnew cases was low (25) relative tothose already known (75) while else-where in the UK we estimate that thisfigure is50 detected and 50 unde-tected We subjected only those pa-tients who had significant endogenousinsulin (C-peptide) levels and did nothave autoantibodies to systematic genetictesting although previous research(141718) and our failure to find anymu-tations in 65 patients who did have sig-nificant C-peptide levels but wereantibody positive support the idea thatthis approach wouldmiss very few casesUCPCR calculation was performed irre-spective of the duration of diabetesand it is acknowledged that some of
the patients tested close to receiving adiagnosis could be producing endoge-nous insulin during the honeymoon pe-riod and if retested over time thatthose patients with type 1 diabeteswould be expected to have decliningC-peptide levels The calculation of UCPCRis best for excluding patients 3 yearsafter diabetes is diagnosed while au-toantibody testing is best for excludingpatients close to diagnosis In thisstudy we wanted to test everyone re-gardless of disease duration so a test-ing method that used both biomarkersworked well If a study was performed ofpurely incident cases which would havean advantage of making the correct di-agnosis early then measuring C-peptidelevels would have little value and furthertesting could be performed on those in-dividuals who had negative results fromtesting for multiple autoantibodies Al-though patients were asked to send aldquopostmealrdquo urine sample the prandialstate of the patient was assumed (andnot observed) therefore we cannot becertain that all UCPCR tests were stimu-lated Our population consisted predomi-nantly (96) of whites and systematicstudies in other especially high-prevalencepopulations are also needed
There aremany strengths of this studyThe result is likely to be representative ofthe clinics studied because 795 of theeligible population took part a result thatshows the high acceptability of this ap-proach in pediatric clinics The systematicbiomarkerndashbased approach that is inde-pendent of clinical features allows atypi-cal patients to be detected (eg thosewith no family history of diabetes) Thisis the first study that has used next-generation sequencing to assess allknown causes of monogenic diabetes al-though themajority of patients (85) hadthe most common types of MODY (GCKHNF1A and HNF4A) so studies that havenot used this approach will have missedonly a few patients
This systematic high-uptake studygives a prevalence of 25 (95 CI 16ndash39) for monogenic diabetes in the UKpediatric population Patients with mono-genic diabetes were identified in everypediatric clinic The successful identifica-tion of patients with monogenic diabe-tes is crucial because they requiredifferent treatment than those withtype 1 or type 2 diabetes The vast major-ity (99) of pediatric patients can be
1886 UK Screening for Pediatric Monogenic Diabetes Diabetes Care Volume 39 November 2016
successfully classified by UCPCR antibodytesting genetic testing and clinical crite-ria UCPCR is a noninvasive and inexpen-sive test which could be more widelyused in the pediatric age group whereit has a high acceptability This screeningalgorithm is a practical approach to de-termining the prevalence of cases in aclinic to ensure the correct diagnosis ofsubtypes of diabetes Confirming a prev-alence of MODY of 25 in the pediatricpopulation indicates that all those in-volved in pediatric diabetes care shouldbe aware of the possibility of an alterna-tive diagnosis and know how to referpatients for genetic testing
Acknowledgments The authors thank the pa-tientswhotookpartinthisstudyandthenurseswhorecruited them for their support with this projectFunding This work presents independent re-search commissioned by the Health InnovationChallenge Fund a parallel funding partnershipbetween theWellcome Trust and the DepartmentofHealth(grantHICF-1009-041)andwassupportedbytheNational Institute forHealthResearch (NIHR)ExeterClinicalResearchFacility and theSouthWestPeninsula Diabetes Research Network MS issupported by the NIHR Exeter Clinical ResearchFacilityTJM is fundedbyanNIHRCSOFellowshipSE and ATH are both Wellcome Trust SeniorInvestigators ERP is a Wellcome Trust New In-vestigator ATH is an NIHR Senior InvestigatorTheviewsexpressed in thispublicationare those
of the authors and not necessarily those of theWellcomeTrust theNHS theNational Institute forHealth Research or the Department of HealthDuality of Interest No potential conflicts ofinterest relevant to this article were reportedAuthor Contributions MS wrote the manu-script and collected and analyzed the data BSanalyzed the data and reviewed and editedthe manuscript SH collected the data andreviewed the manuscript MH coordinatedthe project assistedwith the data and reviewedthe manuscript TJM coordinated the urinaryC-peptide creatinine ratio determination andantibody testing and reviewed the manuscriptKC assistedwith genetic data and reviewed andedited themanuscript RAO contributed to thediscussion and reviewed the manuscript BKdeveloped the protocol submitted the ethicsapplication and reviewed the manuscript CHreviewed the manuscript JC KM CM RSBF SR andSG facilitatedpatient recruitmentwithin their pediatric clinics and reviewed themanuscript SE coordinated the genetic testingand reviewed the manuscript ERP coordi-nated the Tayside arm of the project and re-viewed and edited the manuscript ATHdesigned the study contributed to the discus-sion and reviewed and edited the manuscriptThe UNITED team collected the data MS is theguarantor of this work and as such had fullaccess to all the data in the study and takesresponsibility for the integrity of the data andthe accuracy of the data analysis
References1 Pihoker C Gilliam LK Ellard S et al SEARCHfor Diabetes in Youth Study Group Preva-lence characteristics and clinical diagnosis ofmaturity onset diabetes of the young due to mu-tations inHNF1A HNF4A and glucokinase resultsfrom the SEARCH for Diabetes in Youth J ClinEndocrinol Metab 2013984055ndash40622 Irgens HU Molnes J Johansson BB et al Prev-alence of monogenic diabetes in the population-based Norwegian Childhood Diabetes RegistryDiabetologia 2013561512ndash15193 Carmody D Lindauer KL Naylor RN Adoles-cent non-adherence reveals a genetic cause fordiabetes Diabet Med 201532e20ndashe234 Gandica RG Chung WK Deng L Goland RGallagher MP Identifying monogenic diabetesin a pediatric cohort with presumed type 1 di-abetes Pediatr Diabetes 201516227ndash2335 Lambert AP Ellard S Allen LI et al Identify-ing hepatic nuclear factor 1alpha mutations inchildren and young adults with a clinical diag-nosis of type 1 diabetes Diabetes Care 200326333ndash3376 Thirumalai A Holing E Brown Z Gilliam LK Acase of hepatocyte nuclear factor-1b (TCF2) ma-turity onset diabetes of the youngmisdiagnosedas type 1 diabetes and treated unnecessarilywith insulin J Diabetes 20135462ndash4647 Fendler W Borowiec M Baranowska-Jazwiecka A et al Prevalence of monogenicdiabetes amongst Polish children after a nation-wide genetic screening campaign Diabetologia2012552631ndash26358 Rubio-Cabezas O Edghill EL Argente JHattersley AT Testing for monogenic diabetesamong children and adolescents with antibody-negative clinically defined type 1 diabetes Dia-bet Med 2009261070ndash10749 Murphy R Ellard S Hattersley AT Clinicalimplications of a molecular genetic classifica-tion of monogenic beta-cell diabetes Nat ClinPract Endocrinol Metab 20084200ndash21310 Rubio-Cabezas O Hattersley AT NjoslashlstadPR et al International Society for Pediatricand Adolescent Diabetes ISPAD Clinical PracticeConsensus Guidelines 2014 The diagnosis andmanagement of monogenic diabetes in childrenand adolescents Pediatr Diabetes 201415(Suppl 20)47ndash6411 Craig ME Jefferies C Dabelea D Balde NSeth A Donaghue KC International Societyfor Pediatric and Adolescent Diabetes ISPADClinical Practice Consensus Guidelines 2014Definition epidemiology and classification ofdiabetes in children and adolescents PediatrDiabetes 201415(Suppl 20)4ndash1712 Colclough K Saint-Martin C Timsit J EllardS Bellanne-Chantelot C Clinical utility gene cardfor maturity-onset diabetes of the young Eur JHum Genet 12 February 2014 [Epub ahead ofprint] DOI 101038ejhg20141413 Shields BM Hicks S Shepherd MHColclough K Hattersley AT Ellard S Maturity-onset diabetes of the young (MODY) howmanycases are we missing Diabetologia 2010532504ndash250814 Besser RE Shepherd MH McDonald TJet al Urinary C-peptide creatinine ratio is apractical outpatient tool for identifying hepato-cyte nuclear factor 1-alphahepatocyte nuclearfactor 4-alpha maturity-onset diabetes of the
young from long-duration type 1 diabetes Di-abetes Care 201134286ndash29115 McDonald TJ Knight BA Shields BMBowman P Salzmann MB Hattersley AT Stabil-ity and reproducibility of a single-sample urinaryC-peptidecreatinine ratio and its correlation with24-h urinary C-peptide Clin Chem 2009552035ndash203916 Besser RE Ludvigsson J Jones AG et alUrine C-peptide creatinine ratio is a noninvasivealternative to the mixed-meal tolerance test inchildren and adults with type 1 diabetes Diabe-tes Care 201134607ndash60917 Besser RE Shields BM Hammersley SEet al Home urine C-peptide creatinine ratio(UCPCR) testing can identify type 2 and MODYin pediatric diabetes Pediatr Diabetes 201314181ndash18818 McDonald TJ Colclough K Brown R et alIslet autoantibodies can discriminate maturity-onset diabetes of the young (MODY) from type 1diabetes Diabet Med 2011281028ndash103319 Kanakatti Shankar R Pihoker C Dolan LMet al SEARCH for Diabetes in Youth Study GroupPermanent neonatal diabetes mellitus preva-lence and genetic diagnosis in the SEARCH for Di-abetes in Youth Study Pediatr Diabetes 201314174ndash18020 Hameed S Ellard S Woodhead HJ et alPersistently autoantibody negative (PAN)type 1 diabetes mellitus in children Pediatr Di-abetes 201112142ndash14921 Wheeler BJ Patterson N Love DR et alFrequency and genetic spectrum of maturity-onset diabetes of the young (MODY) in southernNew Zealand J Diabetes Metab Disord 2013124622 Redondo MJ Rodriguez LM Escalante MSmith EO Balasubramanyam A HaymondMW Types of pediatric diabetes mellitus de-fined by anti-islet autoimmunity and randomC-peptide at diagnosis Pediatr Diabetes 201314333ndash34023 Ehtisham S Hattersley AT Dunger DBBarrett TG British Society for Paediatric Endo-crinology and Diabetes Clinical Trials GroupFirst UK survey of paediatric type 2 diabetesand MODY Arch Dis Child 200489526ndash52924 Neu A Feldhahn L Ehehalt S Hub R RankeMB DIARY group Baden-Wurttemberg Type2 diabetes mellitus in children and adolescentsis still a rare disease in Germany a population-based assessment of the prevalence of type 2diabetes and MODY in patients aged 0-20 yearsPediatr Diabetes 200910468ndash47325 Amed S Dean HJ Panagiotopoulos C et alType 2 diabetes medication-induced diabetesand monogenic diabetes in Canadian children aprospective national surveillance study Diabe-tes Care 201033786ndash79126 Galler A Stange T Muller G et al Child-hood Diabetes Registry in Saxony Germany In-cidence of childhood diabetes in children agedless than 15 years and its clinical and metaboliccharacteristics at the time of diagnosis datafrom the Childhood Diabetes Registry of Sax-ony Germany Horm Res Paediatr 201074285ndash29127 Schober E Rami B Grabert M et al DPV-Wiss Initiative of the GermanWorking Group forPaediatric Diabetology and Phenotypical as-pects of maturity-onset diabetes of the young
carediabetesjournalsorg Shepherd and Associates 1887
(MODY diabetes) in comparison with type 2 di-abetes mellitus (T2DM) in children and adoles-cents experience from a large multicentredatabase Diabet Med 200926466ndash47328 Freeman JV Cole TJ Chinn S et al Crosssectional stature and weight reference curvesfor the UK 1990 Arch Dis Child 19957317ndash2429 Ellard S Lango Allen H De Franco E et alImproved genetic testing for monogenic diabe-tes using targeted next-generation sequencingDiabetologia 2013561958ndash196330 Awa WL Thon A Raile K et al DPV-WissStudy Group Genetic and clinical characteristicsof patients with HNF1A gene variations from the
German-Austrian DPV database Eur J Endocri-nol 2011164513ndash52031 Health amp Social Care Information CentreNational diabetes audit 2011-12 report 1 careprocesses and treatment targets CCG and LHGdata tables [Internet] 2013 Available fromhttpwwwhscicgovuksearchcatalogueproductid=13129ampq=22National+diabetes+audit22ampsort=Relevanceampsize=10amppage=1top Ac-cessed 3 January 201632 Diabetes in Scotland Scottish Diabetes Sur-vey 2014 [Internet] 2014 Available from httpwwwdiabetesinscotlandorgukPublicationsSDS2014pdf Accessed 3 January 2016
33 Vaziri-Sani F Delli AJ Elding-Larsson Het al A novel triple mix radiobinding assay forthe three ZnT8 (ZnT8-RWQ) autoantibody vari-ants in children with newly diagnosed diabetesJ Immunol Methods 201137125ndash3734 Yorifuji T Fujimaru R Hosokawa Y et alComprehensive molecular analysis of Japa-nese patients with pediatric-onset MODY-type diabetes mellitus Pediatr Diabetes20121326ndash3235 Chambers C Fouts A Dong F et al Charac-teristics of maturity onset diabetes of the youngin a large diabetes center Pediatr Diabetes201617360ndash367
1888 UK Screening for Pediatric Monogenic Diabetes Diabetes Care Volume 39 November 2016
Table
1mdashAppro
ach
esuse
dto
identify
monogenic
diabetesin
pediatric
populations
Typeofstudy
Country
Area
Initialcohort(n)
Cohortcharacteristics
Testingstrategy
(subgrouptested
)Gen
estested
Prevalen
cein
genetically
tested
Minim
alprevalence
of
monogenic
diabetes
Reference
System
aticstudiesordered
bynumber
instudy
Multicen
terpopulation
based
US
6centers
California
OhioH
awaii
South
Carolina
Washington
596
31)
Diagn
osed20
years
1)AB-ve(3
2)fasting
C-pep
tide$08ngmL
(n=58
6)
1)HNF1AH
NF4A
GCK
1)84(47586
)12
1
2)Diagnosed6months
2)Diagn
osed6months
(n=7)
2)KC
NJ11
INS
ABCC8
2)71
4(57)
02
(total14)
19
Nationwidepopulation
based
Norw
ayNationwide
275
6New
lydiagnosed
age0ndash14
years
1)AB-ve(3
2)and
affected
paren
t(n
=46
)1)
HNF1AH
NF4A
MIDD
1)13
0(646)
11
2
2)AB-veHbA1c75
(58mmolmol)and
notreceivinginsulin
(n=10
)
2)GCK
2)30
0(310)
3)Diagn
osed12
months
(n=24
)3)
KCNJ11
ABCC8
INS
3)16
6(424)
Epidem
iologicald
ata
nationwidegenetictest
results
Poland
3centers
Lodz
Katowice
Gdan
sk
256
8Age
0ndash18
years
1)AB-ve
affected
paren
tnoninsulin
dep
enden
t1)
HNF1AH
NF4A
HNF1B
321(100
311)
31ndash42
7
2)HbA1c75
(58mmolmol)
2)GCK
3)Diagn
osed6months
3)KC
NJ11
ABCC8
INS
4)Syndromicdiabetes
4)WFSAlstrom
Singleped
iatricclinic
population
US
New
York
939
ClinicaldiagnosisT1D
AB-ve(3
3)pluseither
GCK
86
(558)
05
4
Age
6monthsto
20years
HbA1c7
(53mmolmol)and05
unitsinsulinkgday
1year
postdiagnosis
C-pep
tidepositive
or
3genFH(n
=58
)
HNF1A
Pediatricclinicsin
single
city
Australia
Sydney
497
1)Clinicaldiagn
osisT1D
AB-ve(3
4on
2occasion
s)(n
=19
)1)
HNF1AH
NF4A
2)INSKC
NJ11
5(119)
12
20
2)Diagnosed6monthsto
16years
Singleped
iatricclinic
population
Spain
Madrid
252
1)Clinicaldiagn
osisT1D
AB-ve(3
5)(n
=25
)1)
HNF1AH
NF4A
80
(225)
08
8
2)Diagnosed6monthsto
17years
2)KC
NJ11INS
Pediatriccliniccase
histories
New
Zealand
South
Island
160
Pediatricdiabetes
18
years
AB-ve(3
2)(n
=4)
GCK
HNF1B
HNF1A
25(4160
)25
21
Con
tinu
edon
p18
82
carediabetesjournalsorg Shepherd and Associates 1881
1882 UK Screening for Pediatric Monogenic Diabetes Diabetes Care Volume 39 November 2016
autoantibodies (GAD and IA2) to identifythose with autoimmune diabetes Thistest was performed in all participantswith significant endogenous insulin levels(either a UCPCR $02 nmolmmol whilereceiving insulin treatment or not receiv-ing insulin treatment) If islet autoantibodyresults were available from previous test-ing these were used otherwise a bloodsample was taken for antibody testingPatients with GAD or IA2 levels 99thpercentile were deemed islet autoanti-body positive (18) and were consideredto have a diagnosis of type 1 diabetesStage 3 consisted of genetic testing in
participants who were UCPCR positiveand islet autoantibody negative DNAwas extracted using standard methodsfrom a blood sample that was usuallyobtained at the same time as the samplefor islet autoantibody testing Sanger se-quencing analysis of the HNF1A andHNF4A genes and dosage analysis bymultiplex ligation-dependent probe am-plification to detect partial and wholegene deletions of HNF1A HNF4A GCKand HNF1B was undertaken for all pa-tients with additional Sanger sequenc-ing analysis of the GCK gene undertakenfor patients with maximum HbA1c levelsof76 (60 mmolmol) This testingstrategywas performed initially becausethese are the most common genes im-plicated in MODY accounting for95of all MODY cases in the UK (13) andare amenable to treatment change Pa-tients with no pathogenic mutationidentified by Sanger sequencing andmultiplex ligation-dependent probe am-plification then underwent targetednext-generation sequencing to look for
mutations in 29 genes known to causemonogenicdiabetes and themitochondrialmutation m3243AG causing maternallyinherited diabetes and deafness using theassay published by Ellard et al (29)
Statistical AnalysisData were double entered onto a data-base and subsequently cleaned Dataarepresented as proportions andmedian(interquartile range [IQR]) where appro-priate because of the non-normality ofdata Prevalence was calculated as theproportion of patients with monogenicdiabetes out of the total number of pa-tients studied Data were analyzed usingStata version 131
RESULTS
A total of 795 of the eligible popula-tion (n = 808 of 1016) completed thestudy (Fig 2) Fifteen of these partici-pants had previously undergone genetictesting and were already known to havemonogenic diabetes (Table 2)
Patient CharacteristicsA total of 54 of participants were male(441 male 376 female) The median ageat study recruitment was 13 years (IQR =10 16) the median age at diagnosis was8 years (IQR = 4 11) and all individualsreceived a diagnosis of diabetes at6 months of age The median durationof diabeteswas 43 years (IQR = 16 79)The majority (788 participants [96]) ofthe cohort were white reflecting thepopulation demographics in these areasA total of 792 patients (97) were receiv-ing insulin treatment at the time of studyrecruitment including 4 patients whowere receiving treatment with insulin in
addition to metformin Twenty-five pa-tients (3) were noninsulin treated with11 patients receiving oral agents onlyand 14 were being treated withdiet alone The median HbA1c level was86 (IQR = 77 97 [70 mmolmol IQR =61 83]) and the median BMI percentilewas 79 (IQR = 56 94)
Stage 1 UCPCRA total of 547 of 817 patients (67)wereUCPCR negative (02 nmolmol) indi-cating insulin deficiency and weretherefore considered to have type 1 di-abetes and these individuals did notundergo further testing In addition261 patients (32) had significant endoge-nous insulin production ($02 nmolmol)this included 236 patients who weretreated with insulin and 25 patientswho were not treated with insulin
Stage 2 AntibodiesThe 253 patients with significant endog-enous insulin levels underwent isletautoantibody testing which included236 patients who were treated with in-sulin and confirmed to be UCPCR posi-tive through stage 1 of the study and17 patients who were not treated withinsulin Eight of 15 patients who hadpreviously received a diagnosis ofmonogenic diabetes did not undergo an-tibody testing (but none of these weretreated with insulin) and 9 patients didnot return their blood sample for anti-body testing
A total of 179 of 253 participants wereislet autoantibody positive confirming adiagnosis of type 1 diabetes Forty-fiveof these participants were positive toboth GAD and IA2 28 were positive toGAD only 21 were positive to GAD butIA2 was not tested for and 85 were pos-itive to IA2 only indicating the impor-tance of testing for both autoantibodiesThe 74 participants who were antibodynegative continued to stage 3 for genetictesting
Stage 3 Genetic TestingThe prevalence of monogenic diabetesin this UK pediatric diabetes popula-tion that was 20 years of age was25 (95 CI 15ndash39) A total of82 of 808 patients (101) had under-gone genetic testing and 20 of these(24 1 in 4 patients) had monogenicdiabetes (Table 2) Fifteen of 20 patientswere previously known to have mono-genic diabetes (7 GCK MODY 5 HNF1A
Figure 1mdashPathway of testing
carediabetesjournalsorg Shepherd and Associates 1883
MODY 1 HNF4AMODY 1 ABCC8MODYand 1 patientwith typeA insulin resistancedue to a heterozygous INSRmutation) and5 new cases of monogenic diabetes(3 HNF4A MODY 1 HNF1B MODY 1 GCKMODY) were identified during the studyOne of these patients had a dual diagno-sis of HNF4A MODY (heterozygous forthe pArg114Trp mutation) and type 1diabetes (GAD negative as defined inthis study as the 99th percentile andtherefore proceeded to genetic testingbut with a GAD titer of 259975th per-centile and a UCPCR of 021 nmolmol2 years after diagnosis and had receivedcontinuous insulin treatment from thetime of diagnosis) Patients with mono-genic diabetes were found in all six clin-ics with a prevalence varying between12 and 37To assess whether we had missed
cases of monogenic diabetes in thosewith islet autoantibodies 65 of 179 pa-tients with positive autoantibodies un-derwent Sanger sequencing analysis ofthe most common MODY genes (GCKHNF1A and HNF4A) no mutations werefound
Characteristics of Patients Negativeon Genetic TestingDiagnosis was not established using thistesting pathway in 62 participants whowere UCPCR positive islet autoantibodynegative and negative for mutations in
29 genes known to cause monogenicdiabetes Secondary causes of diabeteswere known in two individuals with apreviously recorded diagnosis of cysticfibrosisndashrelated diabetes Twenty-sevenof 62 of these patients (33 of the co-hort) met the diagnostic criteria fortype 2 diabetes (no monogenic or sec-ondary cause BMI $85th percentileand antibody negative [httpwebispadorgsitesdefaultfilesresourcesfilesidf-ispad_diabetes_in_childhood_and_adolescence_guidelines_2011_0pdf]) but were not assessed for insulinresistance or other metabolic features
Uncertainty over the diagnosis re-mained in 33 individuals (4 of thewhole cohort) The most likely diagnosisin these individuals was islet autoanti-body-negative type 1 diabetes becausethey were close to diagnosis (medianduration 08 years [IQR = 04 28]) andwere not overweight (median BMI in the51st percentile [IQR = 43 67]) Twenty-six of 33 of these individuals had a di-abetes duration of 3 years and socould be considered to be within thehoneymoon phase repeating testingfor the UCPCR in these individuals overtime could prove to be useful However5 of 33 individuals had a median diabe-tes duration of 61 years (range 5ndash10years) median BMI in the 53rd percentile(range 46th to 81st percentile) with a
medianUCPCRof 036nmolmmol (range021ndash127 nmolmmol) therefore thediabetes in these individuals should beconsidered atypical and not fitting aclear diagnostic category
Only 194 of the eligible patientswithin these pediatric diabetes popula-tions (n = 198) did not take part in thisstudy This included 13 known patientswith monogenic diabetes (10 patientshad GCK MODY and were thereforenot under the care of a diabetes team3 patientswith HNF1A and 1 patientwithWolfram syndrome) Therefore this co-hort was not biased to include all thosepatients with known monogenic diabe-tes The prevalence of monogenic diabe-tes in those patients recruited was 25comparedwith 66 (P = 00038) in thosepatients not taking part in the study
CONCLUSIONS
We found a prevalence of monogenicdiabetes in patients diagnosed20 yearsof age of 25 (95 CI 16ndash39) bysystematic testing using islet autoanti-bodies C-peptide and targeted next-generation sequencing of all monogenicdiabetes genes Using our approach ofscreening childrenadolescents withdiabetes using C-peptide followed byGAD and IA2 autoantibodies would iden-tify a subpopulation of 10 in whichgenetic testing will have a pick up rate of1 in 4 Using the online probability cal-culator (httpwwwdiabetesgenesorgcontentmody-probability-calculator)could further aid in the identification ofthose individuals who were most likelyto have MODY because in our study18 of 20 patients with monogenic dia-betes were shown to have a 1 in 13chance (or755) post-test probabilityof having MODY
The 25 (95 CI 16ndash39) preva-lence of monogenic diabetes we identi-fied is similar to the prevalence found inthree other large systematic populationstudies (12719) two from predomi-nantly European white populations (Po-land 31ndash42 Norway 11) and onefrom a multiethnic population fromthe US (14) (Table 1) The Polishstudy (7) used targeted case findingspredominantly using clinical criteriasupported by the lack of autoantibodiesand measurable C-peptide levels TheNorwegian population-based study (2)predominantly used antibody negativitycombined with a parental history of
Figure 2mdashPatient progression through pathway
1884 UK Screening for Pediatric Monogenic Diabetes Diabetes Care Volume 39 November 2016
Table
2mdashCharacte
risticsofth
e20patie
nts
identifi
edwith
monogenic
diabetes
StudyID
Gen
eMutatio
n
Protein
effectGen
der
Age
atdiagn
osis
(years)
Diab
etesduratio
n(years)
Initial
treatmen
tCurren
ttreatm
ent
BMI
percen
tileAffectedparen
t
UCPCR
(nmol
mmol)
GAD
IA2
Notes
211GCK
c97_117dup
p(V
al33_Lys39dup)
M3
13Insulin
None
99thMother
357NA
NA
KnownMODY
537GCK
c683CT
p(Th
r228Met)
M11
2Diet
None
NA
Mother
194NA
NA
KnownMODY
Siblin
gof538
538GCK
c683CT
p(Th
r228Met)
M9
1Diet
None
NA
Mother
173NA
NA
KnownMODY
Siblin
gof537
543GCK
c184GA
p(V
al62Met)
M4
02Diet
None
NA
Mother
NA
NA
NA
KnownMODY
Siblin
gof544
544GCK
c184GA
p(V
al62Met)
M3
2Diet
None
NA
Mother
NA
NA
NA
KnownMODY
Siblin
gof543
1396GCK
c1209del
p(Ile404fs)
M14
03Diet
None
71stMother
NA
NA
NA
KnownMODY
8002095GCK
c1019GT
p(Ser340Ile)
M9
5Diet
None
88thFath
er079
Neg
NA
KnownMODY
8002372GCK
c1340GA
p(A
rg447Gln)
M18
06Diet
None
90thNeith
erNottested
Neg
Nottested
New
lyiden
tified
MODY
599HNF1A
c608GA
p(A
rg203His)
F14
05OHA
OHA
99thBoth
paren
ts308
Neg
Neg
KnownMODY
1012HNF1A
c872del
p(Pro
291fs)F
1007
Diet
Diet
99thMother
56Neg
Neg
KnownMODY
Siblin
gof395
395HNF1A
c872del
p(Pro
291fs)F
1401
OHA
OHA
95thMother
58Neg
Neg
KnownMODY
Siblin
gof1012
455HNF1A
c872dup
p(G
ly292fs)F
123
OHA
OHA
57thFath
er086
Neg
Neg
KnownMODY
567HNF1A
c872dup
p(G
ly292fs)M
82
Diet
OHA
94thMother
173Neg
Neg
KnownMODY
686HNF4A
c749TC
p(Leu
250Pro)
M16
07Diet
Diet
99thFath
er474
NA
NA
KnownMODY
1348HNF4A
c340CT
p(A
rg114Trp)
F15
02Insulin
OHA
86thFath
er300
Neg
Neg
New
lyiden
tified
MODY
1203HNF4A
c340CT
p(A
rg114Trp)
M7
2Insulin
Insulin
39thNeith
er021
Neg
Neg
Duald
iagnosis
new
lyiden
tified
HNF4A
knowntyp
e1diab
etes
377HNF4A
c-12GA
p()
F11
2Insulin
Insulin
99thMother
028Neg
Neg
New
lyiden
tified
MODY
854HNF1B
c1-_151+d
elp(0)
(whole
genedeletio
n)
M11
2Insulin
Insulin
9thFath
er071
Neg
Neg
New
lyiden
tified
MODY
555ABCC8
c4139GA
p(A
rg1380His)
F11
8OHA
OHA
4thFath
er300
Neg
Neg
KnownMODY
758INSR
c3706CG
p(P
ro1236A
la)F
123
OHA
Diet
55thMother
907NA
NA
KnownMODY
Ffemale
IDid
entifi
cationMm
aleNAn
otapplicab
legenetic
diagn
osis
mad
eprio
rto
studyNegn
egativeOHAo
ralhypoglycem
icagen
tG
ADnegativede
finedinthis
studyas
99th
percentilebutGAD259
(975thpercentile)M
utations
aredescribed
usingthe
Hum
anGenom
eVariation
Societynom
enclatureguidelines
according
tothe
following
referencesequ
encesG
CKNM_0001623H
NF1A
NM_0005456H
NF4A
NM_1759144A
BCC8
NM_0012871741IN
SRNM_0002082D
iabetes
duratio
nat
timeofstu
dy
carediabetesjournalsorg Shepherd and Associates 1885
diabetes or lack of insulin therapy andHbA1c levels of 75 (58 mmolmol)The lower prevalence (11) probably re-flected that they studied children 0ndash14years of age rather than 0ndash20 years ofage (mean age at diagnosis in our study106 years) and only 10 patients weretested for GCK The US study (119) likeour study used systematic biomarkerscreening with genetic testing performedin all patients who had measurableC-peptide levels and did not have GADand IA2 autoantibodies The lower preva-lence in their cohort probably results fromnon-MODY patients having more ldquotype2 featuresrdquo suggesting a greater propor-tion of patients with young-onset type 2diabetes because the combined preva-lence of MODY in minority individuals wasvery similar to the prevalence of MODY innon-Hispanic white individuals (1) Therearemany other less comprehensive studies(252730) of the prevalence of monogenicdiabetes (Table 1) these are limited bystudying a single clinic using a nonsystem-atic assessment andor not making arobust molecular genetic diagnosis (con-firmed mutations not polymorphisms)Our study indicated a higher propor-
tion of known cases of MODY versusnew cases identified through systematicscreening The 28 patients with previ-ously confirmed MODY (15 who tookpart and 13 who did not take part inthe study) reflect the high levels ofawareness of monogenic diabetes inthese geographical regions The 13 pa-tients previously identified who did nottake part in the study included 9 withGCK MODY (who had been dischargedfrom clinic follow-up) 3 with HNF1AMODY and 1 with Wolfram syndromeThis study shows that clinical recognitionof key phenotypes in patients and theirfamily members can identify the major-ity of pediatric patients (15 of 20 inthis study) However the five new pa-tients identified through this pathwayof screening indicate the need for a sys-tematic approach If this approach wereused in other areas where the recogni-tion of monogenic diabetes is not so ap-parent then a greater proportion of newcases would be identified We havebased our prevalence figures only onthe population recruited in this studyhowever if the 13 patients who did nottake part were taken into account thiscould give a prevalence as high as 33(33 of 1016 patients) There are estimated
to be35000 children and young peoplewith diabetes who are under 19 yearsof age in the UK (3132) If the preva-lence of 25 found in those patientswho took part in this six-clinic surveyreflects the whole of the UK then thissuggests at least 875 expected patientswith MODY in this age group (95CI 560ndash1365) of whom 468 havereceived a diagnosis to date with50 still likely to be misdiagnosedas having type 1 diabetes
This approach of systematic testingcombined with clinical criteria can resultin a diagnosis in 99 of patients andthis is an advantage of this approach be-yond the recognition of monogenic diabe-tes We were able to use C-peptideautoantibody and genetic testing togive a clear diagnosis in 923 of patientsClinical criteria suggest that 33 hadtype 2 diabetes a figure that is very similarto the number of individuals with mono-genic diabetes as seen in other Europeanpopulations (72433) A total of 02 hadsecondary diabetes due to cystic fibrosiswhich probably reflects an underestimateasmanyof these patientswill not attend apediatric diabetes clinic A further 32were within 3 years of having received adiagnosis and probably had antibody-negative type 1 diabetes in the honey-moonperiod There remainedfivepatients(06) who were atypical and hard toclassifydthey may represent atypicaltype 1 diabetes (antibody negative andsignificant C-peptide levels3 years afterdiagnosis) or a presently unrecognizedsubtype of monogenic diabetes
There were limitations to this studyThe geographical areas where the studywas undertaken already had a highawareness of MODY so the number ofnew cases was low (25) relative tothose already known (75) while else-where in the UK we estimate that thisfigure is50 detected and 50 unde-tected We subjected only those pa-tients who had significant endogenousinsulin (C-peptide) levels and did nothave autoantibodies to systematic genetictesting although previous research(141718) and our failure to find anymu-tations in 65 patients who did have sig-nificant C-peptide levels but wereantibody positive support the idea thatthis approach wouldmiss very few casesUCPCR calculation was performed irre-spective of the duration of diabetesand it is acknowledged that some of
the patients tested close to receiving adiagnosis could be producing endoge-nous insulin during the honeymoon pe-riod and if retested over time thatthose patients with type 1 diabeteswould be expected to have decliningC-peptide levels The calculation of UCPCRis best for excluding patients 3 yearsafter diabetes is diagnosed while au-toantibody testing is best for excludingpatients close to diagnosis In thisstudy we wanted to test everyone re-gardless of disease duration so a test-ing method that used both biomarkersworked well If a study was performed ofpurely incident cases which would havean advantage of making the correct di-agnosis early then measuring C-peptidelevels would have little value and furthertesting could be performed on those in-dividuals who had negative results fromtesting for multiple autoantibodies Al-though patients were asked to send aldquopostmealrdquo urine sample the prandialstate of the patient was assumed (andnot observed) therefore we cannot becertain that all UCPCR tests were stimu-lated Our population consisted predomi-nantly (96) of whites and systematicstudies in other especially high-prevalencepopulations are also needed
There aremany strengths of this studyThe result is likely to be representative ofthe clinics studied because 795 of theeligible population took part a result thatshows the high acceptability of this ap-proach in pediatric clinics The systematicbiomarkerndashbased approach that is inde-pendent of clinical features allows atypi-cal patients to be detected (eg thosewith no family history of diabetes) Thisis the first study that has used next-generation sequencing to assess allknown causes of monogenic diabetes al-though themajority of patients (85) hadthe most common types of MODY (GCKHNF1A and HNF4A) so studies that havenot used this approach will have missedonly a few patients
This systematic high-uptake studygives a prevalence of 25 (95 CI 16ndash39) for monogenic diabetes in the UKpediatric population Patients with mono-genic diabetes were identified in everypediatric clinic The successful identifica-tion of patients with monogenic diabe-tes is crucial because they requiredifferent treatment than those withtype 1 or type 2 diabetes The vast major-ity (99) of pediatric patients can be
1886 UK Screening for Pediatric Monogenic Diabetes Diabetes Care Volume 39 November 2016
successfully classified by UCPCR antibodytesting genetic testing and clinical crite-ria UCPCR is a noninvasive and inexpen-sive test which could be more widelyused in the pediatric age group whereit has a high acceptability This screeningalgorithm is a practical approach to de-termining the prevalence of cases in aclinic to ensure the correct diagnosis ofsubtypes of diabetes Confirming a prev-alence of MODY of 25 in the pediatricpopulation indicates that all those in-volved in pediatric diabetes care shouldbe aware of the possibility of an alterna-tive diagnosis and know how to referpatients for genetic testing
Acknowledgments The authors thank the pa-tientswhotookpartinthisstudyandthenurseswhorecruited them for their support with this projectFunding This work presents independent re-search commissioned by the Health InnovationChallenge Fund a parallel funding partnershipbetween theWellcome Trust and the DepartmentofHealth(grantHICF-1009-041)andwassupportedbytheNational Institute forHealthResearch (NIHR)ExeterClinicalResearchFacility and theSouthWestPeninsula Diabetes Research Network MS issupported by the NIHR Exeter Clinical ResearchFacilityTJM is fundedbyanNIHRCSOFellowshipSE and ATH are both Wellcome Trust SeniorInvestigators ERP is a Wellcome Trust New In-vestigator ATH is an NIHR Senior InvestigatorTheviewsexpressed in thispublicationare those
of the authors and not necessarily those of theWellcomeTrust theNHS theNational Institute forHealth Research or the Department of HealthDuality of Interest No potential conflicts ofinterest relevant to this article were reportedAuthor Contributions MS wrote the manu-script and collected and analyzed the data BSanalyzed the data and reviewed and editedthe manuscript SH collected the data andreviewed the manuscript MH coordinatedthe project assistedwith the data and reviewedthe manuscript TJM coordinated the urinaryC-peptide creatinine ratio determination andantibody testing and reviewed the manuscriptKC assistedwith genetic data and reviewed andedited themanuscript RAO contributed to thediscussion and reviewed the manuscript BKdeveloped the protocol submitted the ethicsapplication and reviewed the manuscript CHreviewed the manuscript JC KM CM RSBF SR andSG facilitatedpatient recruitmentwithin their pediatric clinics and reviewed themanuscript SE coordinated the genetic testingand reviewed the manuscript ERP coordi-nated the Tayside arm of the project and re-viewed and edited the manuscript ATHdesigned the study contributed to the discus-sion and reviewed and edited the manuscriptThe UNITED team collected the data MS is theguarantor of this work and as such had fullaccess to all the data in the study and takesresponsibility for the integrity of the data andthe accuracy of the data analysis
References1 Pihoker C Gilliam LK Ellard S et al SEARCHfor Diabetes in Youth Study Group Preva-lence characteristics and clinical diagnosis ofmaturity onset diabetes of the young due to mu-tations inHNF1A HNF4A and glucokinase resultsfrom the SEARCH for Diabetes in Youth J ClinEndocrinol Metab 2013984055ndash40622 Irgens HU Molnes J Johansson BB et al Prev-alence of monogenic diabetes in the population-based Norwegian Childhood Diabetes RegistryDiabetologia 2013561512ndash15193 Carmody D Lindauer KL Naylor RN Adoles-cent non-adherence reveals a genetic cause fordiabetes Diabet Med 201532e20ndashe234 Gandica RG Chung WK Deng L Goland RGallagher MP Identifying monogenic diabetesin a pediatric cohort with presumed type 1 di-abetes Pediatr Diabetes 201516227ndash2335 Lambert AP Ellard S Allen LI et al Identify-ing hepatic nuclear factor 1alpha mutations inchildren and young adults with a clinical diag-nosis of type 1 diabetes Diabetes Care 200326333ndash3376 Thirumalai A Holing E Brown Z Gilliam LK Acase of hepatocyte nuclear factor-1b (TCF2) ma-turity onset diabetes of the youngmisdiagnosedas type 1 diabetes and treated unnecessarilywith insulin J Diabetes 20135462ndash4647 Fendler W Borowiec M Baranowska-Jazwiecka A et al Prevalence of monogenicdiabetes amongst Polish children after a nation-wide genetic screening campaign Diabetologia2012552631ndash26358 Rubio-Cabezas O Edghill EL Argente JHattersley AT Testing for monogenic diabetesamong children and adolescents with antibody-negative clinically defined type 1 diabetes Dia-bet Med 2009261070ndash10749 Murphy R Ellard S Hattersley AT Clinicalimplications of a molecular genetic classifica-tion of monogenic beta-cell diabetes Nat ClinPract Endocrinol Metab 20084200ndash21310 Rubio-Cabezas O Hattersley AT NjoslashlstadPR et al International Society for Pediatricand Adolescent Diabetes ISPAD Clinical PracticeConsensus Guidelines 2014 The diagnosis andmanagement of monogenic diabetes in childrenand adolescents Pediatr Diabetes 201415(Suppl 20)47ndash6411 Craig ME Jefferies C Dabelea D Balde NSeth A Donaghue KC International Societyfor Pediatric and Adolescent Diabetes ISPADClinical Practice Consensus Guidelines 2014Definition epidemiology and classification ofdiabetes in children and adolescents PediatrDiabetes 201415(Suppl 20)4ndash1712 Colclough K Saint-Martin C Timsit J EllardS Bellanne-Chantelot C Clinical utility gene cardfor maturity-onset diabetes of the young Eur JHum Genet 12 February 2014 [Epub ahead ofprint] DOI 101038ejhg20141413 Shields BM Hicks S Shepherd MHColclough K Hattersley AT Ellard S Maturity-onset diabetes of the young (MODY) howmanycases are we missing Diabetologia 2010532504ndash250814 Besser RE Shepherd MH McDonald TJet al Urinary C-peptide creatinine ratio is apractical outpatient tool for identifying hepato-cyte nuclear factor 1-alphahepatocyte nuclearfactor 4-alpha maturity-onset diabetes of the
young from long-duration type 1 diabetes Di-abetes Care 201134286ndash29115 McDonald TJ Knight BA Shields BMBowman P Salzmann MB Hattersley AT Stabil-ity and reproducibility of a single-sample urinaryC-peptidecreatinine ratio and its correlation with24-h urinary C-peptide Clin Chem 2009552035ndash203916 Besser RE Ludvigsson J Jones AG et alUrine C-peptide creatinine ratio is a noninvasivealternative to the mixed-meal tolerance test inchildren and adults with type 1 diabetes Diabe-tes Care 201134607ndash60917 Besser RE Shields BM Hammersley SEet al Home urine C-peptide creatinine ratio(UCPCR) testing can identify type 2 and MODYin pediatric diabetes Pediatr Diabetes 201314181ndash18818 McDonald TJ Colclough K Brown R et alIslet autoantibodies can discriminate maturity-onset diabetes of the young (MODY) from type 1diabetes Diabet Med 2011281028ndash103319 Kanakatti Shankar R Pihoker C Dolan LMet al SEARCH for Diabetes in Youth Study GroupPermanent neonatal diabetes mellitus preva-lence and genetic diagnosis in the SEARCH for Di-abetes in Youth Study Pediatr Diabetes 201314174ndash18020 Hameed S Ellard S Woodhead HJ et alPersistently autoantibody negative (PAN)type 1 diabetes mellitus in children Pediatr Di-abetes 201112142ndash14921 Wheeler BJ Patterson N Love DR et alFrequency and genetic spectrum of maturity-onset diabetes of the young (MODY) in southernNew Zealand J Diabetes Metab Disord 2013124622 Redondo MJ Rodriguez LM Escalante MSmith EO Balasubramanyam A HaymondMW Types of pediatric diabetes mellitus de-fined by anti-islet autoimmunity and randomC-peptide at diagnosis Pediatr Diabetes 201314333ndash34023 Ehtisham S Hattersley AT Dunger DBBarrett TG British Society for Paediatric Endo-crinology and Diabetes Clinical Trials GroupFirst UK survey of paediatric type 2 diabetesand MODY Arch Dis Child 200489526ndash52924 Neu A Feldhahn L Ehehalt S Hub R RankeMB DIARY group Baden-Wurttemberg Type2 diabetes mellitus in children and adolescentsis still a rare disease in Germany a population-based assessment of the prevalence of type 2diabetes and MODY in patients aged 0-20 yearsPediatr Diabetes 200910468ndash47325 Amed S Dean HJ Panagiotopoulos C et alType 2 diabetes medication-induced diabetesand monogenic diabetes in Canadian children aprospective national surveillance study Diabe-tes Care 201033786ndash79126 Galler A Stange T Muller G et al Child-hood Diabetes Registry in Saxony Germany In-cidence of childhood diabetes in children agedless than 15 years and its clinical and metaboliccharacteristics at the time of diagnosis datafrom the Childhood Diabetes Registry of Sax-ony Germany Horm Res Paediatr 201074285ndash29127 Schober E Rami B Grabert M et al DPV-Wiss Initiative of the GermanWorking Group forPaediatric Diabetology and Phenotypical as-pects of maturity-onset diabetes of the young
carediabetesjournalsorg Shepherd and Associates 1887
(MODY diabetes) in comparison with type 2 di-abetes mellitus (T2DM) in children and adoles-cents experience from a large multicentredatabase Diabet Med 200926466ndash47328 Freeman JV Cole TJ Chinn S et al Crosssectional stature and weight reference curvesfor the UK 1990 Arch Dis Child 19957317ndash2429 Ellard S Lango Allen H De Franco E et alImproved genetic testing for monogenic diabe-tes using targeted next-generation sequencingDiabetologia 2013561958ndash196330 Awa WL Thon A Raile K et al DPV-WissStudy Group Genetic and clinical characteristicsof patients with HNF1A gene variations from the
German-Austrian DPV database Eur J Endocri-nol 2011164513ndash52031 Health amp Social Care Information CentreNational diabetes audit 2011-12 report 1 careprocesses and treatment targets CCG and LHGdata tables [Internet] 2013 Available fromhttpwwwhscicgovuksearchcatalogueproductid=13129ampq=22National+diabetes+audit22ampsort=Relevanceampsize=10amppage=1top Ac-cessed 3 January 201632 Diabetes in Scotland Scottish Diabetes Sur-vey 2014 [Internet] 2014 Available from httpwwwdiabetesinscotlandorgukPublicationsSDS2014pdf Accessed 3 January 2016
33 Vaziri-Sani F Delli AJ Elding-Larsson Het al A novel triple mix radiobinding assay forthe three ZnT8 (ZnT8-RWQ) autoantibody vari-ants in children with newly diagnosed diabetesJ Immunol Methods 201137125ndash3734 Yorifuji T Fujimaru R Hosokawa Y et alComprehensive molecular analysis of Japa-nese patients with pediatric-onset MODY-type diabetes mellitus Pediatr Diabetes20121326ndash3235 Chambers C Fouts A Dong F et al Charac-teristics of maturity onset diabetes of the youngin a large diabetes center Pediatr Diabetes201617360ndash367
1888 UK Screening for Pediatric Monogenic Diabetes Diabetes Care Volume 39 November 2016
1882 UK Screening for Pediatric Monogenic Diabetes Diabetes Care Volume 39 November 2016
autoantibodies (GAD and IA2) to identifythose with autoimmune diabetes Thistest was performed in all participantswith significant endogenous insulin levels(either a UCPCR $02 nmolmmol whilereceiving insulin treatment or not receiv-ing insulin treatment) If islet autoantibodyresults were available from previous test-ing these were used otherwise a bloodsample was taken for antibody testingPatients with GAD or IA2 levels 99thpercentile were deemed islet autoanti-body positive (18) and were consideredto have a diagnosis of type 1 diabetesStage 3 consisted of genetic testing in
participants who were UCPCR positiveand islet autoantibody negative DNAwas extracted using standard methodsfrom a blood sample that was usuallyobtained at the same time as the samplefor islet autoantibody testing Sanger se-quencing analysis of the HNF1A andHNF4A genes and dosage analysis bymultiplex ligation-dependent probe am-plification to detect partial and wholegene deletions of HNF1A HNF4A GCKand HNF1B was undertaken for all pa-tients with additional Sanger sequenc-ing analysis of the GCK gene undertakenfor patients with maximum HbA1c levelsof76 (60 mmolmol) This testingstrategywas performed initially becausethese are the most common genes im-plicated in MODY accounting for95of all MODY cases in the UK (13) andare amenable to treatment change Pa-tients with no pathogenic mutationidentified by Sanger sequencing andmultiplex ligation-dependent probe am-plification then underwent targetednext-generation sequencing to look for
mutations in 29 genes known to causemonogenicdiabetes and themitochondrialmutation m3243AG causing maternallyinherited diabetes and deafness using theassay published by Ellard et al (29)
Statistical AnalysisData were double entered onto a data-base and subsequently cleaned Dataarepresented as proportions andmedian(interquartile range [IQR]) where appro-priate because of the non-normality ofdata Prevalence was calculated as theproportion of patients with monogenicdiabetes out of the total number of pa-tients studied Data were analyzed usingStata version 131
RESULTS
A total of 795 of the eligible popula-tion (n = 808 of 1016) completed thestudy (Fig 2) Fifteen of these partici-pants had previously undergone genetictesting and were already known to havemonogenic diabetes (Table 2)
Patient CharacteristicsA total of 54 of participants were male(441 male 376 female) The median ageat study recruitment was 13 years (IQR =10 16) the median age at diagnosis was8 years (IQR = 4 11) and all individualsreceived a diagnosis of diabetes at6 months of age The median durationof diabeteswas 43 years (IQR = 16 79)The majority (788 participants [96]) ofthe cohort were white reflecting thepopulation demographics in these areasA total of 792 patients (97) were receiv-ing insulin treatment at the time of studyrecruitment including 4 patients whowere receiving treatment with insulin in
addition to metformin Twenty-five pa-tients (3) were noninsulin treated with11 patients receiving oral agents onlyand 14 were being treated withdiet alone The median HbA1c level was86 (IQR = 77 97 [70 mmolmol IQR =61 83]) and the median BMI percentilewas 79 (IQR = 56 94)
Stage 1 UCPCRA total of 547 of 817 patients (67)wereUCPCR negative (02 nmolmol) indi-cating insulin deficiency and weretherefore considered to have type 1 di-abetes and these individuals did notundergo further testing In addition261 patients (32) had significant endoge-nous insulin production ($02 nmolmol)this included 236 patients who weretreated with insulin and 25 patientswho were not treated with insulin
Stage 2 AntibodiesThe 253 patients with significant endog-enous insulin levels underwent isletautoantibody testing which included236 patients who were treated with in-sulin and confirmed to be UCPCR posi-tive through stage 1 of the study and17 patients who were not treated withinsulin Eight of 15 patients who hadpreviously received a diagnosis ofmonogenic diabetes did not undergo an-tibody testing (but none of these weretreated with insulin) and 9 patients didnot return their blood sample for anti-body testing
A total of 179 of 253 participants wereislet autoantibody positive confirming adiagnosis of type 1 diabetes Forty-fiveof these participants were positive toboth GAD and IA2 28 were positive toGAD only 21 were positive to GAD butIA2 was not tested for and 85 were pos-itive to IA2 only indicating the impor-tance of testing for both autoantibodiesThe 74 participants who were antibodynegative continued to stage 3 for genetictesting
Stage 3 Genetic TestingThe prevalence of monogenic diabetesin this UK pediatric diabetes popula-tion that was 20 years of age was25 (95 CI 15ndash39) A total of82 of 808 patients (101) had under-gone genetic testing and 20 of these(24 1 in 4 patients) had monogenicdiabetes (Table 2) Fifteen of 20 patientswere previously known to have mono-genic diabetes (7 GCK MODY 5 HNF1A
Figure 1mdashPathway of testing
carediabetesjournalsorg Shepherd and Associates 1883
MODY 1 HNF4AMODY 1 ABCC8MODYand 1 patientwith typeA insulin resistancedue to a heterozygous INSRmutation) and5 new cases of monogenic diabetes(3 HNF4A MODY 1 HNF1B MODY 1 GCKMODY) were identified during the studyOne of these patients had a dual diagno-sis of HNF4A MODY (heterozygous forthe pArg114Trp mutation) and type 1diabetes (GAD negative as defined inthis study as the 99th percentile andtherefore proceeded to genetic testingbut with a GAD titer of 259975th per-centile and a UCPCR of 021 nmolmol2 years after diagnosis and had receivedcontinuous insulin treatment from thetime of diagnosis) Patients with mono-genic diabetes were found in all six clin-ics with a prevalence varying between12 and 37To assess whether we had missed
cases of monogenic diabetes in thosewith islet autoantibodies 65 of 179 pa-tients with positive autoantibodies un-derwent Sanger sequencing analysis ofthe most common MODY genes (GCKHNF1A and HNF4A) no mutations werefound
Characteristics of Patients Negativeon Genetic TestingDiagnosis was not established using thistesting pathway in 62 participants whowere UCPCR positive islet autoantibodynegative and negative for mutations in
29 genes known to cause monogenicdiabetes Secondary causes of diabeteswere known in two individuals with apreviously recorded diagnosis of cysticfibrosisndashrelated diabetes Twenty-sevenof 62 of these patients (33 of the co-hort) met the diagnostic criteria fortype 2 diabetes (no monogenic or sec-ondary cause BMI $85th percentileand antibody negative [httpwebispadorgsitesdefaultfilesresourcesfilesidf-ispad_diabetes_in_childhood_and_adolescence_guidelines_2011_0pdf]) but were not assessed for insulinresistance or other metabolic features
Uncertainty over the diagnosis re-mained in 33 individuals (4 of thewhole cohort) The most likely diagnosisin these individuals was islet autoanti-body-negative type 1 diabetes becausethey were close to diagnosis (medianduration 08 years [IQR = 04 28]) andwere not overweight (median BMI in the51st percentile [IQR = 43 67]) Twenty-six of 33 of these individuals had a di-abetes duration of 3 years and socould be considered to be within thehoneymoon phase repeating testingfor the UCPCR in these individuals overtime could prove to be useful However5 of 33 individuals had a median diabe-tes duration of 61 years (range 5ndash10years) median BMI in the 53rd percentile(range 46th to 81st percentile) with a
medianUCPCRof 036nmolmmol (range021ndash127 nmolmmol) therefore thediabetes in these individuals should beconsidered atypical and not fitting aclear diagnostic category
Only 194 of the eligible patientswithin these pediatric diabetes popula-tions (n = 198) did not take part in thisstudy This included 13 known patientswith monogenic diabetes (10 patientshad GCK MODY and were thereforenot under the care of a diabetes team3 patientswith HNF1A and 1 patientwithWolfram syndrome) Therefore this co-hort was not biased to include all thosepatients with known monogenic diabe-tes The prevalence of monogenic diabe-tes in those patients recruited was 25comparedwith 66 (P = 00038) in thosepatients not taking part in the study
CONCLUSIONS
We found a prevalence of monogenicdiabetes in patients diagnosed20 yearsof age of 25 (95 CI 16ndash39) bysystematic testing using islet autoanti-bodies C-peptide and targeted next-generation sequencing of all monogenicdiabetes genes Using our approach ofscreening childrenadolescents withdiabetes using C-peptide followed byGAD and IA2 autoantibodies would iden-tify a subpopulation of 10 in whichgenetic testing will have a pick up rate of1 in 4 Using the online probability cal-culator (httpwwwdiabetesgenesorgcontentmody-probability-calculator)could further aid in the identification ofthose individuals who were most likelyto have MODY because in our study18 of 20 patients with monogenic dia-betes were shown to have a 1 in 13chance (or755) post-test probabilityof having MODY
The 25 (95 CI 16ndash39) preva-lence of monogenic diabetes we identi-fied is similar to the prevalence found inthree other large systematic populationstudies (12719) two from predomi-nantly European white populations (Po-land 31ndash42 Norway 11) and onefrom a multiethnic population fromthe US (14) (Table 1) The Polishstudy (7) used targeted case findingspredominantly using clinical criteriasupported by the lack of autoantibodiesand measurable C-peptide levels TheNorwegian population-based study (2)predominantly used antibody negativitycombined with a parental history of
Figure 2mdashPatient progression through pathway
1884 UK Screening for Pediatric Monogenic Diabetes Diabetes Care Volume 39 November 2016
Table
2mdashCharacte
risticsofth
e20patie
nts
identifi
edwith
monogenic
diabetes
StudyID
Gen
eMutatio
n
Protein
effectGen
der
Age
atdiagn
osis
(years)
Diab
etesduratio
n(years)
Initial
treatmen
tCurren
ttreatm
ent
BMI
percen
tileAffectedparen
t
UCPCR
(nmol
mmol)
GAD
IA2
Notes
211GCK
c97_117dup
p(V
al33_Lys39dup)
M3
13Insulin
None
99thMother
357NA
NA
KnownMODY
537GCK
c683CT
p(Th
r228Met)
M11
2Diet
None
NA
Mother
194NA
NA
KnownMODY
Siblin
gof538
538GCK
c683CT
p(Th
r228Met)
M9
1Diet
None
NA
Mother
173NA
NA
KnownMODY
Siblin
gof537
543GCK
c184GA
p(V
al62Met)
M4
02Diet
None
NA
Mother
NA
NA
NA
KnownMODY
Siblin
gof544
544GCK
c184GA
p(V
al62Met)
M3
2Diet
None
NA
Mother
NA
NA
NA
KnownMODY
Siblin
gof543
1396GCK
c1209del
p(Ile404fs)
M14
03Diet
None
71stMother
NA
NA
NA
KnownMODY
8002095GCK
c1019GT
p(Ser340Ile)
M9
5Diet
None
88thFath
er079
Neg
NA
KnownMODY
8002372GCK
c1340GA
p(A
rg447Gln)
M18
06Diet
None
90thNeith
erNottested
Neg
Nottested
New
lyiden
tified
MODY
599HNF1A
c608GA
p(A
rg203His)
F14
05OHA
OHA
99thBoth
paren
ts308
Neg
Neg
KnownMODY
1012HNF1A
c872del
p(Pro
291fs)F
1007
Diet
Diet
99thMother
56Neg
Neg
KnownMODY
Siblin
gof395
395HNF1A
c872del
p(Pro
291fs)F
1401
OHA
OHA
95thMother
58Neg
Neg
KnownMODY
Siblin
gof1012
455HNF1A
c872dup
p(G
ly292fs)F
123
OHA
OHA
57thFath
er086
Neg
Neg
KnownMODY
567HNF1A
c872dup
p(G
ly292fs)M
82
Diet
OHA
94thMother
173Neg
Neg
KnownMODY
686HNF4A
c749TC
p(Leu
250Pro)
M16
07Diet
Diet
99thFath
er474
NA
NA
KnownMODY
1348HNF4A
c340CT
p(A
rg114Trp)
F15
02Insulin
OHA
86thFath
er300
Neg
Neg
New
lyiden
tified
MODY
1203HNF4A
c340CT
p(A
rg114Trp)
M7
2Insulin
Insulin
39thNeith
er021
Neg
Neg
Duald
iagnosis
new
lyiden
tified
HNF4A
knowntyp
e1diab
etes
377HNF4A
c-12GA
p()
F11
2Insulin
Insulin
99thMother
028Neg
Neg
New
lyiden
tified
MODY
854HNF1B
c1-_151+d
elp(0)
(whole
genedeletio
n)
M11
2Insulin
Insulin
9thFath
er071
Neg
Neg
New
lyiden
tified
MODY
555ABCC8
c4139GA
p(A
rg1380His)
F11
8OHA
OHA
4thFath
er300
Neg
Neg
KnownMODY
758INSR
c3706CG
p(P
ro1236A
la)F
123
OHA
Diet
55thMother
907NA
NA
KnownMODY
Ffemale
IDid
entifi
cationMm
aleNAn
otapplicab
legenetic
diagn
osis
mad
eprio
rto
studyNegn
egativeOHAo
ralhypoglycem
icagen
tG
ADnegativede
finedinthis
studyas
99th
percentilebutGAD259
(975thpercentile)M
utations
aredescribed
usingthe
Hum
anGenom
eVariation
Societynom
enclatureguidelines
according
tothe
following
referencesequ
encesG
CKNM_0001623H
NF1A
NM_0005456H
NF4A
NM_1759144A
BCC8
NM_0012871741IN
SRNM_0002082D
iabetes
duratio
nat
timeofstu
dy
carediabetesjournalsorg Shepherd and Associates 1885
diabetes or lack of insulin therapy andHbA1c levels of 75 (58 mmolmol)The lower prevalence (11) probably re-flected that they studied children 0ndash14years of age rather than 0ndash20 years ofage (mean age at diagnosis in our study106 years) and only 10 patients weretested for GCK The US study (119) likeour study used systematic biomarkerscreening with genetic testing performedin all patients who had measurableC-peptide levels and did not have GADand IA2 autoantibodies The lower preva-lence in their cohort probably results fromnon-MODY patients having more ldquotype2 featuresrdquo suggesting a greater propor-tion of patients with young-onset type 2diabetes because the combined preva-lence of MODY in minority individuals wasvery similar to the prevalence of MODY innon-Hispanic white individuals (1) Therearemany other less comprehensive studies(252730) of the prevalence of monogenicdiabetes (Table 1) these are limited bystudying a single clinic using a nonsystem-atic assessment andor not making arobust molecular genetic diagnosis (con-firmed mutations not polymorphisms)Our study indicated a higher propor-
tion of known cases of MODY versusnew cases identified through systematicscreening The 28 patients with previ-ously confirmed MODY (15 who tookpart and 13 who did not take part inthe study) reflect the high levels ofawareness of monogenic diabetes inthese geographical regions The 13 pa-tients previously identified who did nottake part in the study included 9 withGCK MODY (who had been dischargedfrom clinic follow-up) 3 with HNF1AMODY and 1 with Wolfram syndromeThis study shows that clinical recognitionof key phenotypes in patients and theirfamily members can identify the major-ity of pediatric patients (15 of 20 inthis study) However the five new pa-tients identified through this pathwayof screening indicate the need for a sys-tematic approach If this approach wereused in other areas where the recogni-tion of monogenic diabetes is not so ap-parent then a greater proportion of newcases would be identified We havebased our prevalence figures only onthe population recruited in this studyhowever if the 13 patients who did nottake part were taken into account thiscould give a prevalence as high as 33(33 of 1016 patients) There are estimated
to be35000 children and young peoplewith diabetes who are under 19 yearsof age in the UK (3132) If the preva-lence of 25 found in those patientswho took part in this six-clinic surveyreflects the whole of the UK then thissuggests at least 875 expected patientswith MODY in this age group (95CI 560ndash1365) of whom 468 havereceived a diagnosis to date with50 still likely to be misdiagnosedas having type 1 diabetes
This approach of systematic testingcombined with clinical criteria can resultin a diagnosis in 99 of patients andthis is an advantage of this approach be-yond the recognition of monogenic diabe-tes We were able to use C-peptideautoantibody and genetic testing togive a clear diagnosis in 923 of patientsClinical criteria suggest that 33 hadtype 2 diabetes a figure that is very similarto the number of individuals with mono-genic diabetes as seen in other Europeanpopulations (72433) A total of 02 hadsecondary diabetes due to cystic fibrosiswhich probably reflects an underestimateasmanyof these patientswill not attend apediatric diabetes clinic A further 32were within 3 years of having received adiagnosis and probably had antibody-negative type 1 diabetes in the honey-moonperiod There remainedfivepatients(06) who were atypical and hard toclassifydthey may represent atypicaltype 1 diabetes (antibody negative andsignificant C-peptide levels3 years afterdiagnosis) or a presently unrecognizedsubtype of monogenic diabetes
There were limitations to this studyThe geographical areas where the studywas undertaken already had a highawareness of MODY so the number ofnew cases was low (25) relative tothose already known (75) while else-where in the UK we estimate that thisfigure is50 detected and 50 unde-tected We subjected only those pa-tients who had significant endogenousinsulin (C-peptide) levels and did nothave autoantibodies to systematic genetictesting although previous research(141718) and our failure to find anymu-tations in 65 patients who did have sig-nificant C-peptide levels but wereantibody positive support the idea thatthis approach wouldmiss very few casesUCPCR calculation was performed irre-spective of the duration of diabetesand it is acknowledged that some of
the patients tested close to receiving adiagnosis could be producing endoge-nous insulin during the honeymoon pe-riod and if retested over time thatthose patients with type 1 diabeteswould be expected to have decliningC-peptide levels The calculation of UCPCRis best for excluding patients 3 yearsafter diabetes is diagnosed while au-toantibody testing is best for excludingpatients close to diagnosis In thisstudy we wanted to test everyone re-gardless of disease duration so a test-ing method that used both biomarkersworked well If a study was performed ofpurely incident cases which would havean advantage of making the correct di-agnosis early then measuring C-peptidelevels would have little value and furthertesting could be performed on those in-dividuals who had negative results fromtesting for multiple autoantibodies Al-though patients were asked to send aldquopostmealrdquo urine sample the prandialstate of the patient was assumed (andnot observed) therefore we cannot becertain that all UCPCR tests were stimu-lated Our population consisted predomi-nantly (96) of whites and systematicstudies in other especially high-prevalencepopulations are also needed
There aremany strengths of this studyThe result is likely to be representative ofthe clinics studied because 795 of theeligible population took part a result thatshows the high acceptability of this ap-proach in pediatric clinics The systematicbiomarkerndashbased approach that is inde-pendent of clinical features allows atypi-cal patients to be detected (eg thosewith no family history of diabetes) Thisis the first study that has used next-generation sequencing to assess allknown causes of monogenic diabetes al-though themajority of patients (85) hadthe most common types of MODY (GCKHNF1A and HNF4A) so studies that havenot used this approach will have missedonly a few patients
This systematic high-uptake studygives a prevalence of 25 (95 CI 16ndash39) for monogenic diabetes in the UKpediatric population Patients with mono-genic diabetes were identified in everypediatric clinic The successful identifica-tion of patients with monogenic diabe-tes is crucial because they requiredifferent treatment than those withtype 1 or type 2 diabetes The vast major-ity (99) of pediatric patients can be
1886 UK Screening for Pediatric Monogenic Diabetes Diabetes Care Volume 39 November 2016
successfully classified by UCPCR antibodytesting genetic testing and clinical crite-ria UCPCR is a noninvasive and inexpen-sive test which could be more widelyused in the pediatric age group whereit has a high acceptability This screeningalgorithm is a practical approach to de-termining the prevalence of cases in aclinic to ensure the correct diagnosis ofsubtypes of diabetes Confirming a prev-alence of MODY of 25 in the pediatricpopulation indicates that all those in-volved in pediatric diabetes care shouldbe aware of the possibility of an alterna-tive diagnosis and know how to referpatients for genetic testing
Acknowledgments The authors thank the pa-tientswhotookpartinthisstudyandthenurseswhorecruited them for their support with this projectFunding This work presents independent re-search commissioned by the Health InnovationChallenge Fund a parallel funding partnershipbetween theWellcome Trust and the DepartmentofHealth(grantHICF-1009-041)andwassupportedbytheNational Institute forHealthResearch (NIHR)ExeterClinicalResearchFacility and theSouthWestPeninsula Diabetes Research Network MS issupported by the NIHR Exeter Clinical ResearchFacilityTJM is fundedbyanNIHRCSOFellowshipSE and ATH are both Wellcome Trust SeniorInvestigators ERP is a Wellcome Trust New In-vestigator ATH is an NIHR Senior InvestigatorTheviewsexpressed in thispublicationare those
of the authors and not necessarily those of theWellcomeTrust theNHS theNational Institute forHealth Research or the Department of HealthDuality of Interest No potential conflicts ofinterest relevant to this article were reportedAuthor Contributions MS wrote the manu-script and collected and analyzed the data BSanalyzed the data and reviewed and editedthe manuscript SH collected the data andreviewed the manuscript MH coordinatedthe project assistedwith the data and reviewedthe manuscript TJM coordinated the urinaryC-peptide creatinine ratio determination andantibody testing and reviewed the manuscriptKC assistedwith genetic data and reviewed andedited themanuscript RAO contributed to thediscussion and reviewed the manuscript BKdeveloped the protocol submitted the ethicsapplication and reviewed the manuscript CHreviewed the manuscript JC KM CM RSBF SR andSG facilitatedpatient recruitmentwithin their pediatric clinics and reviewed themanuscript SE coordinated the genetic testingand reviewed the manuscript ERP coordi-nated the Tayside arm of the project and re-viewed and edited the manuscript ATHdesigned the study contributed to the discus-sion and reviewed and edited the manuscriptThe UNITED team collected the data MS is theguarantor of this work and as such had fullaccess to all the data in the study and takesresponsibility for the integrity of the data andthe accuracy of the data analysis
References1 Pihoker C Gilliam LK Ellard S et al SEARCHfor Diabetes in Youth Study Group Preva-lence characteristics and clinical diagnosis ofmaturity onset diabetes of the young due to mu-tations inHNF1A HNF4A and glucokinase resultsfrom the SEARCH for Diabetes in Youth J ClinEndocrinol Metab 2013984055ndash40622 Irgens HU Molnes J Johansson BB et al Prev-alence of monogenic diabetes in the population-based Norwegian Childhood Diabetes RegistryDiabetologia 2013561512ndash15193 Carmody D Lindauer KL Naylor RN Adoles-cent non-adherence reveals a genetic cause fordiabetes Diabet Med 201532e20ndashe234 Gandica RG Chung WK Deng L Goland RGallagher MP Identifying monogenic diabetesin a pediatric cohort with presumed type 1 di-abetes Pediatr Diabetes 201516227ndash2335 Lambert AP Ellard S Allen LI et al Identify-ing hepatic nuclear factor 1alpha mutations inchildren and young adults with a clinical diag-nosis of type 1 diabetes Diabetes Care 200326333ndash3376 Thirumalai A Holing E Brown Z Gilliam LK Acase of hepatocyte nuclear factor-1b (TCF2) ma-turity onset diabetes of the youngmisdiagnosedas type 1 diabetes and treated unnecessarilywith insulin J Diabetes 20135462ndash4647 Fendler W Borowiec M Baranowska-Jazwiecka A et al Prevalence of monogenicdiabetes amongst Polish children after a nation-wide genetic screening campaign Diabetologia2012552631ndash26358 Rubio-Cabezas O Edghill EL Argente JHattersley AT Testing for monogenic diabetesamong children and adolescents with antibody-negative clinically defined type 1 diabetes Dia-bet Med 2009261070ndash10749 Murphy R Ellard S Hattersley AT Clinicalimplications of a molecular genetic classifica-tion of monogenic beta-cell diabetes Nat ClinPract Endocrinol Metab 20084200ndash21310 Rubio-Cabezas O Hattersley AT NjoslashlstadPR et al International Society for Pediatricand Adolescent Diabetes ISPAD Clinical PracticeConsensus Guidelines 2014 The diagnosis andmanagement of monogenic diabetes in childrenand adolescents Pediatr Diabetes 201415(Suppl 20)47ndash6411 Craig ME Jefferies C Dabelea D Balde NSeth A Donaghue KC International Societyfor Pediatric and Adolescent Diabetes ISPADClinical Practice Consensus Guidelines 2014Definition epidemiology and classification ofdiabetes in children and adolescents PediatrDiabetes 201415(Suppl 20)4ndash1712 Colclough K Saint-Martin C Timsit J EllardS Bellanne-Chantelot C Clinical utility gene cardfor maturity-onset diabetes of the young Eur JHum Genet 12 February 2014 [Epub ahead ofprint] DOI 101038ejhg20141413 Shields BM Hicks S Shepherd MHColclough K Hattersley AT Ellard S Maturity-onset diabetes of the young (MODY) howmanycases are we missing Diabetologia 2010532504ndash250814 Besser RE Shepherd MH McDonald TJet al Urinary C-peptide creatinine ratio is apractical outpatient tool for identifying hepato-cyte nuclear factor 1-alphahepatocyte nuclearfactor 4-alpha maturity-onset diabetes of the
young from long-duration type 1 diabetes Di-abetes Care 201134286ndash29115 McDonald TJ Knight BA Shields BMBowman P Salzmann MB Hattersley AT Stabil-ity and reproducibility of a single-sample urinaryC-peptidecreatinine ratio and its correlation with24-h urinary C-peptide Clin Chem 2009552035ndash203916 Besser RE Ludvigsson J Jones AG et alUrine C-peptide creatinine ratio is a noninvasivealternative to the mixed-meal tolerance test inchildren and adults with type 1 diabetes Diabe-tes Care 201134607ndash60917 Besser RE Shields BM Hammersley SEet al Home urine C-peptide creatinine ratio(UCPCR) testing can identify type 2 and MODYin pediatric diabetes Pediatr Diabetes 201314181ndash18818 McDonald TJ Colclough K Brown R et alIslet autoantibodies can discriminate maturity-onset diabetes of the young (MODY) from type 1diabetes Diabet Med 2011281028ndash103319 Kanakatti Shankar R Pihoker C Dolan LMet al SEARCH for Diabetes in Youth Study GroupPermanent neonatal diabetes mellitus preva-lence and genetic diagnosis in the SEARCH for Di-abetes in Youth Study Pediatr Diabetes 201314174ndash18020 Hameed S Ellard S Woodhead HJ et alPersistently autoantibody negative (PAN)type 1 diabetes mellitus in children Pediatr Di-abetes 201112142ndash14921 Wheeler BJ Patterson N Love DR et alFrequency and genetic spectrum of maturity-onset diabetes of the young (MODY) in southernNew Zealand J Diabetes Metab Disord 2013124622 Redondo MJ Rodriguez LM Escalante MSmith EO Balasubramanyam A HaymondMW Types of pediatric diabetes mellitus de-fined by anti-islet autoimmunity and randomC-peptide at diagnosis Pediatr Diabetes 201314333ndash34023 Ehtisham S Hattersley AT Dunger DBBarrett TG British Society for Paediatric Endo-crinology and Diabetes Clinical Trials GroupFirst UK survey of paediatric type 2 diabetesand MODY Arch Dis Child 200489526ndash52924 Neu A Feldhahn L Ehehalt S Hub R RankeMB DIARY group Baden-Wurttemberg Type2 diabetes mellitus in children and adolescentsis still a rare disease in Germany a population-based assessment of the prevalence of type 2diabetes and MODY in patients aged 0-20 yearsPediatr Diabetes 200910468ndash47325 Amed S Dean HJ Panagiotopoulos C et alType 2 diabetes medication-induced diabetesand monogenic diabetes in Canadian children aprospective national surveillance study Diabe-tes Care 201033786ndash79126 Galler A Stange T Muller G et al Child-hood Diabetes Registry in Saxony Germany In-cidence of childhood diabetes in children agedless than 15 years and its clinical and metaboliccharacteristics at the time of diagnosis datafrom the Childhood Diabetes Registry of Sax-ony Germany Horm Res Paediatr 201074285ndash29127 Schober E Rami B Grabert M et al DPV-Wiss Initiative of the GermanWorking Group forPaediatric Diabetology and Phenotypical as-pects of maturity-onset diabetes of the young
carediabetesjournalsorg Shepherd and Associates 1887
(MODY diabetes) in comparison with type 2 di-abetes mellitus (T2DM) in children and adoles-cents experience from a large multicentredatabase Diabet Med 200926466ndash47328 Freeman JV Cole TJ Chinn S et al Crosssectional stature and weight reference curvesfor the UK 1990 Arch Dis Child 19957317ndash2429 Ellard S Lango Allen H De Franco E et alImproved genetic testing for monogenic diabe-tes using targeted next-generation sequencingDiabetologia 2013561958ndash196330 Awa WL Thon A Raile K et al DPV-WissStudy Group Genetic and clinical characteristicsof patients with HNF1A gene variations from the
German-Austrian DPV database Eur J Endocri-nol 2011164513ndash52031 Health amp Social Care Information CentreNational diabetes audit 2011-12 report 1 careprocesses and treatment targets CCG and LHGdata tables [Internet] 2013 Available fromhttpwwwhscicgovuksearchcatalogueproductid=13129ampq=22National+diabetes+audit22ampsort=Relevanceampsize=10amppage=1top Ac-cessed 3 January 201632 Diabetes in Scotland Scottish Diabetes Sur-vey 2014 [Internet] 2014 Available from httpwwwdiabetesinscotlandorgukPublicationsSDS2014pdf Accessed 3 January 2016
33 Vaziri-Sani F Delli AJ Elding-Larsson Het al A novel triple mix radiobinding assay forthe three ZnT8 (ZnT8-RWQ) autoantibody vari-ants in children with newly diagnosed diabetesJ Immunol Methods 201137125ndash3734 Yorifuji T Fujimaru R Hosokawa Y et alComprehensive molecular analysis of Japa-nese patients with pediatric-onset MODY-type diabetes mellitus Pediatr Diabetes20121326ndash3235 Chambers C Fouts A Dong F et al Charac-teristics of maturity onset diabetes of the youngin a large diabetes center Pediatr Diabetes201617360ndash367
1888 UK Screening for Pediatric Monogenic Diabetes Diabetes Care Volume 39 November 2016
autoantibodies (GAD and IA2) to identifythose with autoimmune diabetes Thistest was performed in all participantswith significant endogenous insulin levels(either a UCPCR $02 nmolmmol whilereceiving insulin treatment or not receiv-ing insulin treatment) If islet autoantibodyresults were available from previous test-ing these were used otherwise a bloodsample was taken for antibody testingPatients with GAD or IA2 levels 99thpercentile were deemed islet autoanti-body positive (18) and were consideredto have a diagnosis of type 1 diabetesStage 3 consisted of genetic testing in
participants who were UCPCR positiveand islet autoantibody negative DNAwas extracted using standard methodsfrom a blood sample that was usuallyobtained at the same time as the samplefor islet autoantibody testing Sanger se-quencing analysis of the HNF1A andHNF4A genes and dosage analysis bymultiplex ligation-dependent probe am-plification to detect partial and wholegene deletions of HNF1A HNF4A GCKand HNF1B was undertaken for all pa-tients with additional Sanger sequenc-ing analysis of the GCK gene undertakenfor patients with maximum HbA1c levelsof76 (60 mmolmol) This testingstrategywas performed initially becausethese are the most common genes im-plicated in MODY accounting for95of all MODY cases in the UK (13) andare amenable to treatment change Pa-tients with no pathogenic mutationidentified by Sanger sequencing andmultiplex ligation-dependent probe am-plification then underwent targetednext-generation sequencing to look for
mutations in 29 genes known to causemonogenicdiabetes and themitochondrialmutation m3243AG causing maternallyinherited diabetes and deafness using theassay published by Ellard et al (29)
Statistical AnalysisData were double entered onto a data-base and subsequently cleaned Dataarepresented as proportions andmedian(interquartile range [IQR]) where appro-priate because of the non-normality ofdata Prevalence was calculated as theproportion of patients with monogenicdiabetes out of the total number of pa-tients studied Data were analyzed usingStata version 131
RESULTS
A total of 795 of the eligible popula-tion (n = 808 of 1016) completed thestudy (Fig 2) Fifteen of these partici-pants had previously undergone genetictesting and were already known to havemonogenic diabetes (Table 2)
Patient CharacteristicsA total of 54 of participants were male(441 male 376 female) The median ageat study recruitment was 13 years (IQR =10 16) the median age at diagnosis was8 years (IQR = 4 11) and all individualsreceived a diagnosis of diabetes at6 months of age The median durationof diabeteswas 43 years (IQR = 16 79)The majority (788 participants [96]) ofthe cohort were white reflecting thepopulation demographics in these areasA total of 792 patients (97) were receiv-ing insulin treatment at the time of studyrecruitment including 4 patients whowere receiving treatment with insulin in
addition to metformin Twenty-five pa-tients (3) were noninsulin treated with11 patients receiving oral agents onlyand 14 were being treated withdiet alone The median HbA1c level was86 (IQR = 77 97 [70 mmolmol IQR =61 83]) and the median BMI percentilewas 79 (IQR = 56 94)
Stage 1 UCPCRA total of 547 of 817 patients (67)wereUCPCR negative (02 nmolmol) indi-cating insulin deficiency and weretherefore considered to have type 1 di-abetes and these individuals did notundergo further testing In addition261 patients (32) had significant endoge-nous insulin production ($02 nmolmol)this included 236 patients who weretreated with insulin and 25 patientswho were not treated with insulin
Stage 2 AntibodiesThe 253 patients with significant endog-enous insulin levels underwent isletautoantibody testing which included236 patients who were treated with in-sulin and confirmed to be UCPCR posi-tive through stage 1 of the study and17 patients who were not treated withinsulin Eight of 15 patients who hadpreviously received a diagnosis ofmonogenic diabetes did not undergo an-tibody testing (but none of these weretreated with insulin) and 9 patients didnot return their blood sample for anti-body testing
A total of 179 of 253 participants wereislet autoantibody positive confirming adiagnosis of type 1 diabetes Forty-fiveof these participants were positive toboth GAD and IA2 28 were positive toGAD only 21 were positive to GAD butIA2 was not tested for and 85 were pos-itive to IA2 only indicating the impor-tance of testing for both autoantibodiesThe 74 participants who were antibodynegative continued to stage 3 for genetictesting
Stage 3 Genetic TestingThe prevalence of monogenic diabetesin this UK pediatric diabetes popula-tion that was 20 years of age was25 (95 CI 15ndash39) A total of82 of 808 patients (101) had under-gone genetic testing and 20 of these(24 1 in 4 patients) had monogenicdiabetes (Table 2) Fifteen of 20 patientswere previously known to have mono-genic diabetes (7 GCK MODY 5 HNF1A
Figure 1mdashPathway of testing
carediabetesjournalsorg Shepherd and Associates 1883
MODY 1 HNF4AMODY 1 ABCC8MODYand 1 patientwith typeA insulin resistancedue to a heterozygous INSRmutation) and5 new cases of monogenic diabetes(3 HNF4A MODY 1 HNF1B MODY 1 GCKMODY) were identified during the studyOne of these patients had a dual diagno-sis of HNF4A MODY (heterozygous forthe pArg114Trp mutation) and type 1diabetes (GAD negative as defined inthis study as the 99th percentile andtherefore proceeded to genetic testingbut with a GAD titer of 259975th per-centile and a UCPCR of 021 nmolmol2 years after diagnosis and had receivedcontinuous insulin treatment from thetime of diagnosis) Patients with mono-genic diabetes were found in all six clin-ics with a prevalence varying between12 and 37To assess whether we had missed
cases of monogenic diabetes in thosewith islet autoantibodies 65 of 179 pa-tients with positive autoantibodies un-derwent Sanger sequencing analysis ofthe most common MODY genes (GCKHNF1A and HNF4A) no mutations werefound
Characteristics of Patients Negativeon Genetic TestingDiagnosis was not established using thistesting pathway in 62 participants whowere UCPCR positive islet autoantibodynegative and negative for mutations in
29 genes known to cause monogenicdiabetes Secondary causes of diabeteswere known in two individuals with apreviously recorded diagnosis of cysticfibrosisndashrelated diabetes Twenty-sevenof 62 of these patients (33 of the co-hort) met the diagnostic criteria fortype 2 diabetes (no monogenic or sec-ondary cause BMI $85th percentileand antibody negative [httpwebispadorgsitesdefaultfilesresourcesfilesidf-ispad_diabetes_in_childhood_and_adolescence_guidelines_2011_0pdf]) but were not assessed for insulinresistance or other metabolic features
Uncertainty over the diagnosis re-mained in 33 individuals (4 of thewhole cohort) The most likely diagnosisin these individuals was islet autoanti-body-negative type 1 diabetes becausethey were close to diagnosis (medianduration 08 years [IQR = 04 28]) andwere not overweight (median BMI in the51st percentile [IQR = 43 67]) Twenty-six of 33 of these individuals had a di-abetes duration of 3 years and socould be considered to be within thehoneymoon phase repeating testingfor the UCPCR in these individuals overtime could prove to be useful However5 of 33 individuals had a median diabe-tes duration of 61 years (range 5ndash10years) median BMI in the 53rd percentile(range 46th to 81st percentile) with a
medianUCPCRof 036nmolmmol (range021ndash127 nmolmmol) therefore thediabetes in these individuals should beconsidered atypical and not fitting aclear diagnostic category
Only 194 of the eligible patientswithin these pediatric diabetes popula-tions (n = 198) did not take part in thisstudy This included 13 known patientswith monogenic diabetes (10 patientshad GCK MODY and were thereforenot under the care of a diabetes team3 patientswith HNF1A and 1 patientwithWolfram syndrome) Therefore this co-hort was not biased to include all thosepatients with known monogenic diabe-tes The prevalence of monogenic diabe-tes in those patients recruited was 25comparedwith 66 (P = 00038) in thosepatients not taking part in the study
CONCLUSIONS
We found a prevalence of monogenicdiabetes in patients diagnosed20 yearsof age of 25 (95 CI 16ndash39) bysystematic testing using islet autoanti-bodies C-peptide and targeted next-generation sequencing of all monogenicdiabetes genes Using our approach ofscreening childrenadolescents withdiabetes using C-peptide followed byGAD and IA2 autoantibodies would iden-tify a subpopulation of 10 in whichgenetic testing will have a pick up rate of1 in 4 Using the online probability cal-culator (httpwwwdiabetesgenesorgcontentmody-probability-calculator)could further aid in the identification ofthose individuals who were most likelyto have MODY because in our study18 of 20 patients with monogenic dia-betes were shown to have a 1 in 13chance (or755) post-test probabilityof having MODY
The 25 (95 CI 16ndash39) preva-lence of monogenic diabetes we identi-fied is similar to the prevalence found inthree other large systematic populationstudies (12719) two from predomi-nantly European white populations (Po-land 31ndash42 Norway 11) and onefrom a multiethnic population fromthe US (14) (Table 1) The Polishstudy (7) used targeted case findingspredominantly using clinical criteriasupported by the lack of autoantibodiesand measurable C-peptide levels TheNorwegian population-based study (2)predominantly used antibody negativitycombined with a parental history of
Figure 2mdashPatient progression through pathway
1884 UK Screening for Pediatric Monogenic Diabetes Diabetes Care Volume 39 November 2016
Table
2mdashCharacte
risticsofth
e20patie
nts
identifi
edwith
monogenic
diabetes
StudyID
Gen
eMutatio
n
Protein
effectGen
der
Age
atdiagn
osis
(years)
Diab
etesduratio
n(years)
Initial
treatmen
tCurren
ttreatm
ent
BMI
percen
tileAffectedparen
t
UCPCR
(nmol
mmol)
GAD
IA2
Notes
211GCK
c97_117dup
p(V
al33_Lys39dup)
M3
13Insulin
None
99thMother
357NA
NA
KnownMODY
537GCK
c683CT
p(Th
r228Met)
M11
2Diet
None
NA
Mother
194NA
NA
KnownMODY
Siblin
gof538
538GCK
c683CT
p(Th
r228Met)
M9
1Diet
None
NA
Mother
173NA
NA
KnownMODY
Siblin
gof537
543GCK
c184GA
p(V
al62Met)
M4
02Diet
None
NA
Mother
NA
NA
NA
KnownMODY
Siblin
gof544
544GCK
c184GA
p(V
al62Met)
M3
2Diet
None
NA
Mother
NA
NA
NA
KnownMODY
Siblin
gof543
1396GCK
c1209del
p(Ile404fs)
M14
03Diet
None
71stMother
NA
NA
NA
KnownMODY
8002095GCK
c1019GT
p(Ser340Ile)
M9
5Diet
None
88thFath
er079
Neg
NA
KnownMODY
8002372GCK
c1340GA
p(A
rg447Gln)
M18
06Diet
None
90thNeith
erNottested
Neg
Nottested
New
lyiden
tified
MODY
599HNF1A
c608GA
p(A
rg203His)
F14
05OHA
OHA
99thBoth
paren
ts308
Neg
Neg
KnownMODY
1012HNF1A
c872del
p(Pro
291fs)F
1007
Diet
Diet
99thMother
56Neg
Neg
KnownMODY
Siblin
gof395
395HNF1A
c872del
p(Pro
291fs)F
1401
OHA
OHA
95thMother
58Neg
Neg
KnownMODY
Siblin
gof1012
455HNF1A
c872dup
p(G
ly292fs)F
123
OHA
OHA
57thFath
er086
Neg
Neg
KnownMODY
567HNF1A
c872dup
p(G
ly292fs)M
82
Diet
OHA
94thMother
173Neg
Neg
KnownMODY
686HNF4A
c749TC
p(Leu
250Pro)
M16
07Diet
Diet
99thFath
er474
NA
NA
KnownMODY
1348HNF4A
c340CT
p(A
rg114Trp)
F15
02Insulin
OHA
86thFath
er300
Neg
Neg
New
lyiden
tified
MODY
1203HNF4A
c340CT
p(A
rg114Trp)
M7
2Insulin
Insulin
39thNeith
er021
Neg
Neg
Duald
iagnosis
new
lyiden
tified
HNF4A
knowntyp
e1diab
etes
377HNF4A
c-12GA
p()
F11
2Insulin
Insulin
99thMother
028Neg
Neg
New
lyiden
tified
MODY
854HNF1B
c1-_151+d
elp(0)
(whole
genedeletio
n)
M11
2Insulin
Insulin
9thFath
er071
Neg
Neg
New
lyiden
tified
MODY
555ABCC8
c4139GA
p(A
rg1380His)
F11
8OHA
OHA
4thFath
er300
Neg
Neg
KnownMODY
758INSR
c3706CG
p(P
ro1236A
la)F
123
OHA
Diet
55thMother
907NA
NA
KnownMODY
Ffemale
IDid
entifi
cationMm
aleNAn
otapplicab
legenetic
diagn
osis
mad
eprio
rto
studyNegn
egativeOHAo
ralhypoglycem
icagen
tG
ADnegativede
finedinthis
studyas
99th
percentilebutGAD259
(975thpercentile)M
utations
aredescribed
usingthe
Hum
anGenom
eVariation
Societynom
enclatureguidelines
according
tothe
following
referencesequ
encesG
CKNM_0001623H
NF1A
NM_0005456H
NF4A
NM_1759144A
BCC8
NM_0012871741IN
SRNM_0002082D
iabetes
duratio
nat
timeofstu
dy
carediabetesjournalsorg Shepherd and Associates 1885
diabetes or lack of insulin therapy andHbA1c levels of 75 (58 mmolmol)The lower prevalence (11) probably re-flected that they studied children 0ndash14years of age rather than 0ndash20 years ofage (mean age at diagnosis in our study106 years) and only 10 patients weretested for GCK The US study (119) likeour study used systematic biomarkerscreening with genetic testing performedin all patients who had measurableC-peptide levels and did not have GADand IA2 autoantibodies The lower preva-lence in their cohort probably results fromnon-MODY patients having more ldquotype2 featuresrdquo suggesting a greater propor-tion of patients with young-onset type 2diabetes because the combined preva-lence of MODY in minority individuals wasvery similar to the prevalence of MODY innon-Hispanic white individuals (1) Therearemany other less comprehensive studies(252730) of the prevalence of monogenicdiabetes (Table 1) these are limited bystudying a single clinic using a nonsystem-atic assessment andor not making arobust molecular genetic diagnosis (con-firmed mutations not polymorphisms)Our study indicated a higher propor-
tion of known cases of MODY versusnew cases identified through systematicscreening The 28 patients with previ-ously confirmed MODY (15 who tookpart and 13 who did not take part inthe study) reflect the high levels ofawareness of monogenic diabetes inthese geographical regions The 13 pa-tients previously identified who did nottake part in the study included 9 withGCK MODY (who had been dischargedfrom clinic follow-up) 3 with HNF1AMODY and 1 with Wolfram syndromeThis study shows that clinical recognitionof key phenotypes in patients and theirfamily members can identify the major-ity of pediatric patients (15 of 20 inthis study) However the five new pa-tients identified through this pathwayof screening indicate the need for a sys-tematic approach If this approach wereused in other areas where the recogni-tion of monogenic diabetes is not so ap-parent then a greater proportion of newcases would be identified We havebased our prevalence figures only onthe population recruited in this studyhowever if the 13 patients who did nottake part were taken into account thiscould give a prevalence as high as 33(33 of 1016 patients) There are estimated
to be35000 children and young peoplewith diabetes who are under 19 yearsof age in the UK (3132) If the preva-lence of 25 found in those patientswho took part in this six-clinic surveyreflects the whole of the UK then thissuggests at least 875 expected patientswith MODY in this age group (95CI 560ndash1365) of whom 468 havereceived a diagnosis to date with50 still likely to be misdiagnosedas having type 1 diabetes
This approach of systematic testingcombined with clinical criteria can resultin a diagnosis in 99 of patients andthis is an advantage of this approach be-yond the recognition of monogenic diabe-tes We were able to use C-peptideautoantibody and genetic testing togive a clear diagnosis in 923 of patientsClinical criteria suggest that 33 hadtype 2 diabetes a figure that is very similarto the number of individuals with mono-genic diabetes as seen in other Europeanpopulations (72433) A total of 02 hadsecondary diabetes due to cystic fibrosiswhich probably reflects an underestimateasmanyof these patientswill not attend apediatric diabetes clinic A further 32were within 3 years of having received adiagnosis and probably had antibody-negative type 1 diabetes in the honey-moonperiod There remainedfivepatients(06) who were atypical and hard toclassifydthey may represent atypicaltype 1 diabetes (antibody negative andsignificant C-peptide levels3 years afterdiagnosis) or a presently unrecognizedsubtype of monogenic diabetes
There were limitations to this studyThe geographical areas where the studywas undertaken already had a highawareness of MODY so the number ofnew cases was low (25) relative tothose already known (75) while else-where in the UK we estimate that thisfigure is50 detected and 50 unde-tected We subjected only those pa-tients who had significant endogenousinsulin (C-peptide) levels and did nothave autoantibodies to systematic genetictesting although previous research(141718) and our failure to find anymu-tations in 65 patients who did have sig-nificant C-peptide levels but wereantibody positive support the idea thatthis approach wouldmiss very few casesUCPCR calculation was performed irre-spective of the duration of diabetesand it is acknowledged that some of
the patients tested close to receiving adiagnosis could be producing endoge-nous insulin during the honeymoon pe-riod and if retested over time thatthose patients with type 1 diabeteswould be expected to have decliningC-peptide levels The calculation of UCPCRis best for excluding patients 3 yearsafter diabetes is diagnosed while au-toantibody testing is best for excludingpatients close to diagnosis In thisstudy we wanted to test everyone re-gardless of disease duration so a test-ing method that used both biomarkersworked well If a study was performed ofpurely incident cases which would havean advantage of making the correct di-agnosis early then measuring C-peptidelevels would have little value and furthertesting could be performed on those in-dividuals who had negative results fromtesting for multiple autoantibodies Al-though patients were asked to send aldquopostmealrdquo urine sample the prandialstate of the patient was assumed (andnot observed) therefore we cannot becertain that all UCPCR tests were stimu-lated Our population consisted predomi-nantly (96) of whites and systematicstudies in other especially high-prevalencepopulations are also needed
There aremany strengths of this studyThe result is likely to be representative ofthe clinics studied because 795 of theeligible population took part a result thatshows the high acceptability of this ap-proach in pediatric clinics The systematicbiomarkerndashbased approach that is inde-pendent of clinical features allows atypi-cal patients to be detected (eg thosewith no family history of diabetes) Thisis the first study that has used next-generation sequencing to assess allknown causes of monogenic diabetes al-though themajority of patients (85) hadthe most common types of MODY (GCKHNF1A and HNF4A) so studies that havenot used this approach will have missedonly a few patients
This systematic high-uptake studygives a prevalence of 25 (95 CI 16ndash39) for monogenic diabetes in the UKpediatric population Patients with mono-genic diabetes were identified in everypediatric clinic The successful identifica-tion of patients with monogenic diabe-tes is crucial because they requiredifferent treatment than those withtype 1 or type 2 diabetes The vast major-ity (99) of pediatric patients can be
1886 UK Screening for Pediatric Monogenic Diabetes Diabetes Care Volume 39 November 2016
successfully classified by UCPCR antibodytesting genetic testing and clinical crite-ria UCPCR is a noninvasive and inexpen-sive test which could be more widelyused in the pediatric age group whereit has a high acceptability This screeningalgorithm is a practical approach to de-termining the prevalence of cases in aclinic to ensure the correct diagnosis ofsubtypes of diabetes Confirming a prev-alence of MODY of 25 in the pediatricpopulation indicates that all those in-volved in pediatric diabetes care shouldbe aware of the possibility of an alterna-tive diagnosis and know how to referpatients for genetic testing
Acknowledgments The authors thank the pa-tientswhotookpartinthisstudyandthenurseswhorecruited them for their support with this projectFunding This work presents independent re-search commissioned by the Health InnovationChallenge Fund a parallel funding partnershipbetween theWellcome Trust and the DepartmentofHealth(grantHICF-1009-041)andwassupportedbytheNational Institute forHealthResearch (NIHR)ExeterClinicalResearchFacility and theSouthWestPeninsula Diabetes Research Network MS issupported by the NIHR Exeter Clinical ResearchFacilityTJM is fundedbyanNIHRCSOFellowshipSE and ATH are both Wellcome Trust SeniorInvestigators ERP is a Wellcome Trust New In-vestigator ATH is an NIHR Senior InvestigatorTheviewsexpressed in thispublicationare those
of the authors and not necessarily those of theWellcomeTrust theNHS theNational Institute forHealth Research or the Department of HealthDuality of Interest No potential conflicts ofinterest relevant to this article were reportedAuthor Contributions MS wrote the manu-script and collected and analyzed the data BSanalyzed the data and reviewed and editedthe manuscript SH collected the data andreviewed the manuscript MH coordinatedthe project assistedwith the data and reviewedthe manuscript TJM coordinated the urinaryC-peptide creatinine ratio determination andantibody testing and reviewed the manuscriptKC assistedwith genetic data and reviewed andedited themanuscript RAO contributed to thediscussion and reviewed the manuscript BKdeveloped the protocol submitted the ethicsapplication and reviewed the manuscript CHreviewed the manuscript JC KM CM RSBF SR andSG facilitatedpatient recruitmentwithin their pediatric clinics and reviewed themanuscript SE coordinated the genetic testingand reviewed the manuscript ERP coordi-nated the Tayside arm of the project and re-viewed and edited the manuscript ATHdesigned the study contributed to the discus-sion and reviewed and edited the manuscriptThe UNITED team collected the data MS is theguarantor of this work and as such had fullaccess to all the data in the study and takesresponsibility for the integrity of the data andthe accuracy of the data analysis
References1 Pihoker C Gilliam LK Ellard S et al SEARCHfor Diabetes in Youth Study Group Preva-lence characteristics and clinical diagnosis ofmaturity onset diabetes of the young due to mu-tations inHNF1A HNF4A and glucokinase resultsfrom the SEARCH for Diabetes in Youth J ClinEndocrinol Metab 2013984055ndash40622 Irgens HU Molnes J Johansson BB et al Prev-alence of monogenic diabetes in the population-based Norwegian Childhood Diabetes RegistryDiabetologia 2013561512ndash15193 Carmody D Lindauer KL Naylor RN Adoles-cent non-adherence reveals a genetic cause fordiabetes Diabet Med 201532e20ndashe234 Gandica RG Chung WK Deng L Goland RGallagher MP Identifying monogenic diabetesin a pediatric cohort with presumed type 1 di-abetes Pediatr Diabetes 201516227ndash2335 Lambert AP Ellard S Allen LI et al Identify-ing hepatic nuclear factor 1alpha mutations inchildren and young adults with a clinical diag-nosis of type 1 diabetes Diabetes Care 200326333ndash3376 Thirumalai A Holing E Brown Z Gilliam LK Acase of hepatocyte nuclear factor-1b (TCF2) ma-turity onset diabetes of the youngmisdiagnosedas type 1 diabetes and treated unnecessarilywith insulin J Diabetes 20135462ndash4647 Fendler W Borowiec M Baranowska-Jazwiecka A et al Prevalence of monogenicdiabetes amongst Polish children after a nation-wide genetic screening campaign Diabetologia2012552631ndash26358 Rubio-Cabezas O Edghill EL Argente JHattersley AT Testing for monogenic diabetesamong children and adolescents with antibody-negative clinically defined type 1 diabetes Dia-bet Med 2009261070ndash10749 Murphy R Ellard S Hattersley AT Clinicalimplications of a molecular genetic classifica-tion of monogenic beta-cell diabetes Nat ClinPract Endocrinol Metab 20084200ndash21310 Rubio-Cabezas O Hattersley AT NjoslashlstadPR et al International Society for Pediatricand Adolescent Diabetes ISPAD Clinical PracticeConsensus Guidelines 2014 The diagnosis andmanagement of monogenic diabetes in childrenand adolescents Pediatr Diabetes 201415(Suppl 20)47ndash6411 Craig ME Jefferies C Dabelea D Balde NSeth A Donaghue KC International Societyfor Pediatric and Adolescent Diabetes ISPADClinical Practice Consensus Guidelines 2014Definition epidemiology and classification ofdiabetes in children and adolescents PediatrDiabetes 201415(Suppl 20)4ndash1712 Colclough K Saint-Martin C Timsit J EllardS Bellanne-Chantelot C Clinical utility gene cardfor maturity-onset diabetes of the young Eur JHum Genet 12 February 2014 [Epub ahead ofprint] DOI 101038ejhg20141413 Shields BM Hicks S Shepherd MHColclough K Hattersley AT Ellard S Maturity-onset diabetes of the young (MODY) howmanycases are we missing Diabetologia 2010532504ndash250814 Besser RE Shepherd MH McDonald TJet al Urinary C-peptide creatinine ratio is apractical outpatient tool for identifying hepato-cyte nuclear factor 1-alphahepatocyte nuclearfactor 4-alpha maturity-onset diabetes of the
young from long-duration type 1 diabetes Di-abetes Care 201134286ndash29115 McDonald TJ Knight BA Shields BMBowman P Salzmann MB Hattersley AT Stabil-ity and reproducibility of a single-sample urinaryC-peptidecreatinine ratio and its correlation with24-h urinary C-peptide Clin Chem 2009552035ndash203916 Besser RE Ludvigsson J Jones AG et alUrine C-peptide creatinine ratio is a noninvasivealternative to the mixed-meal tolerance test inchildren and adults with type 1 diabetes Diabe-tes Care 201134607ndash60917 Besser RE Shields BM Hammersley SEet al Home urine C-peptide creatinine ratio(UCPCR) testing can identify type 2 and MODYin pediatric diabetes Pediatr Diabetes 201314181ndash18818 McDonald TJ Colclough K Brown R et alIslet autoantibodies can discriminate maturity-onset diabetes of the young (MODY) from type 1diabetes Diabet Med 2011281028ndash103319 Kanakatti Shankar R Pihoker C Dolan LMet al SEARCH for Diabetes in Youth Study GroupPermanent neonatal diabetes mellitus preva-lence and genetic diagnosis in the SEARCH for Di-abetes in Youth Study Pediatr Diabetes 201314174ndash18020 Hameed S Ellard S Woodhead HJ et alPersistently autoantibody negative (PAN)type 1 diabetes mellitus in children Pediatr Di-abetes 201112142ndash14921 Wheeler BJ Patterson N Love DR et alFrequency and genetic spectrum of maturity-onset diabetes of the young (MODY) in southernNew Zealand J Diabetes Metab Disord 2013124622 Redondo MJ Rodriguez LM Escalante MSmith EO Balasubramanyam A HaymondMW Types of pediatric diabetes mellitus de-fined by anti-islet autoimmunity and randomC-peptide at diagnosis Pediatr Diabetes 201314333ndash34023 Ehtisham S Hattersley AT Dunger DBBarrett TG British Society for Paediatric Endo-crinology and Diabetes Clinical Trials GroupFirst UK survey of paediatric type 2 diabetesand MODY Arch Dis Child 200489526ndash52924 Neu A Feldhahn L Ehehalt S Hub R RankeMB DIARY group Baden-Wurttemberg Type2 diabetes mellitus in children and adolescentsis still a rare disease in Germany a population-based assessment of the prevalence of type 2diabetes and MODY in patients aged 0-20 yearsPediatr Diabetes 200910468ndash47325 Amed S Dean HJ Panagiotopoulos C et alType 2 diabetes medication-induced diabetesand monogenic diabetes in Canadian children aprospective national surveillance study Diabe-tes Care 201033786ndash79126 Galler A Stange T Muller G et al Child-hood Diabetes Registry in Saxony Germany In-cidence of childhood diabetes in children agedless than 15 years and its clinical and metaboliccharacteristics at the time of diagnosis datafrom the Childhood Diabetes Registry of Sax-ony Germany Horm Res Paediatr 201074285ndash29127 Schober E Rami B Grabert M et al DPV-Wiss Initiative of the GermanWorking Group forPaediatric Diabetology and Phenotypical as-pects of maturity-onset diabetes of the young
carediabetesjournalsorg Shepherd and Associates 1887
(MODY diabetes) in comparison with type 2 di-abetes mellitus (T2DM) in children and adoles-cents experience from a large multicentredatabase Diabet Med 200926466ndash47328 Freeman JV Cole TJ Chinn S et al Crosssectional stature and weight reference curvesfor the UK 1990 Arch Dis Child 19957317ndash2429 Ellard S Lango Allen H De Franco E et alImproved genetic testing for monogenic diabe-tes using targeted next-generation sequencingDiabetologia 2013561958ndash196330 Awa WL Thon A Raile K et al DPV-WissStudy Group Genetic and clinical characteristicsof patients with HNF1A gene variations from the
German-Austrian DPV database Eur J Endocri-nol 2011164513ndash52031 Health amp Social Care Information CentreNational diabetes audit 2011-12 report 1 careprocesses and treatment targets CCG and LHGdata tables [Internet] 2013 Available fromhttpwwwhscicgovuksearchcatalogueproductid=13129ampq=22National+diabetes+audit22ampsort=Relevanceampsize=10amppage=1top Ac-cessed 3 January 201632 Diabetes in Scotland Scottish Diabetes Sur-vey 2014 [Internet] 2014 Available from httpwwwdiabetesinscotlandorgukPublicationsSDS2014pdf Accessed 3 January 2016
33 Vaziri-Sani F Delli AJ Elding-Larsson Het al A novel triple mix radiobinding assay forthe three ZnT8 (ZnT8-RWQ) autoantibody vari-ants in children with newly diagnosed diabetesJ Immunol Methods 201137125ndash3734 Yorifuji T Fujimaru R Hosokawa Y et alComprehensive molecular analysis of Japa-nese patients with pediatric-onset MODY-type diabetes mellitus Pediatr Diabetes20121326ndash3235 Chambers C Fouts A Dong F et al Charac-teristics of maturity onset diabetes of the youngin a large diabetes center Pediatr Diabetes201617360ndash367
1888 UK Screening for Pediatric Monogenic Diabetes Diabetes Care Volume 39 November 2016
MODY 1 HNF4AMODY 1 ABCC8MODYand 1 patientwith typeA insulin resistancedue to a heterozygous INSRmutation) and5 new cases of monogenic diabetes(3 HNF4A MODY 1 HNF1B MODY 1 GCKMODY) were identified during the studyOne of these patients had a dual diagno-sis of HNF4A MODY (heterozygous forthe pArg114Trp mutation) and type 1diabetes (GAD negative as defined inthis study as the 99th percentile andtherefore proceeded to genetic testingbut with a GAD titer of 259975th per-centile and a UCPCR of 021 nmolmol2 years after diagnosis and had receivedcontinuous insulin treatment from thetime of diagnosis) Patients with mono-genic diabetes were found in all six clin-ics with a prevalence varying between12 and 37To assess whether we had missed
cases of monogenic diabetes in thosewith islet autoantibodies 65 of 179 pa-tients with positive autoantibodies un-derwent Sanger sequencing analysis ofthe most common MODY genes (GCKHNF1A and HNF4A) no mutations werefound
Characteristics of Patients Negativeon Genetic TestingDiagnosis was not established using thistesting pathway in 62 participants whowere UCPCR positive islet autoantibodynegative and negative for mutations in
29 genes known to cause monogenicdiabetes Secondary causes of diabeteswere known in two individuals with apreviously recorded diagnosis of cysticfibrosisndashrelated diabetes Twenty-sevenof 62 of these patients (33 of the co-hort) met the diagnostic criteria fortype 2 diabetes (no monogenic or sec-ondary cause BMI $85th percentileand antibody negative [httpwebispadorgsitesdefaultfilesresourcesfilesidf-ispad_diabetes_in_childhood_and_adolescence_guidelines_2011_0pdf]) but were not assessed for insulinresistance or other metabolic features
Uncertainty over the diagnosis re-mained in 33 individuals (4 of thewhole cohort) The most likely diagnosisin these individuals was islet autoanti-body-negative type 1 diabetes becausethey were close to diagnosis (medianduration 08 years [IQR = 04 28]) andwere not overweight (median BMI in the51st percentile [IQR = 43 67]) Twenty-six of 33 of these individuals had a di-abetes duration of 3 years and socould be considered to be within thehoneymoon phase repeating testingfor the UCPCR in these individuals overtime could prove to be useful However5 of 33 individuals had a median diabe-tes duration of 61 years (range 5ndash10years) median BMI in the 53rd percentile(range 46th to 81st percentile) with a
medianUCPCRof 036nmolmmol (range021ndash127 nmolmmol) therefore thediabetes in these individuals should beconsidered atypical and not fitting aclear diagnostic category
Only 194 of the eligible patientswithin these pediatric diabetes popula-tions (n = 198) did not take part in thisstudy This included 13 known patientswith monogenic diabetes (10 patientshad GCK MODY and were thereforenot under the care of a diabetes team3 patientswith HNF1A and 1 patientwithWolfram syndrome) Therefore this co-hort was not biased to include all thosepatients with known monogenic diabe-tes The prevalence of monogenic diabe-tes in those patients recruited was 25comparedwith 66 (P = 00038) in thosepatients not taking part in the study
CONCLUSIONS
We found a prevalence of monogenicdiabetes in patients diagnosed20 yearsof age of 25 (95 CI 16ndash39) bysystematic testing using islet autoanti-bodies C-peptide and targeted next-generation sequencing of all monogenicdiabetes genes Using our approach ofscreening childrenadolescents withdiabetes using C-peptide followed byGAD and IA2 autoantibodies would iden-tify a subpopulation of 10 in whichgenetic testing will have a pick up rate of1 in 4 Using the online probability cal-culator (httpwwwdiabetesgenesorgcontentmody-probability-calculator)could further aid in the identification ofthose individuals who were most likelyto have MODY because in our study18 of 20 patients with monogenic dia-betes were shown to have a 1 in 13chance (or755) post-test probabilityof having MODY
The 25 (95 CI 16ndash39) preva-lence of monogenic diabetes we identi-fied is similar to the prevalence found inthree other large systematic populationstudies (12719) two from predomi-nantly European white populations (Po-land 31ndash42 Norway 11) and onefrom a multiethnic population fromthe US (14) (Table 1) The Polishstudy (7) used targeted case findingspredominantly using clinical criteriasupported by the lack of autoantibodiesand measurable C-peptide levels TheNorwegian population-based study (2)predominantly used antibody negativitycombined with a parental history of
Figure 2mdashPatient progression through pathway
1884 UK Screening for Pediatric Monogenic Diabetes Diabetes Care Volume 39 November 2016
Table
2mdashCharacte
risticsofth
e20patie
nts
identifi
edwith
monogenic
diabetes
StudyID
Gen
eMutatio
n
Protein
effectGen
der
Age
atdiagn
osis
(years)
Diab
etesduratio
n(years)
Initial
treatmen
tCurren
ttreatm
ent
BMI
percen
tileAffectedparen
t
UCPCR
(nmol
mmol)
GAD
IA2
Notes
211GCK
c97_117dup
p(V
al33_Lys39dup)
M3
13Insulin
None
99thMother
357NA
NA
KnownMODY
537GCK
c683CT
p(Th
r228Met)
M11
2Diet
None
NA
Mother
194NA
NA
KnownMODY
Siblin
gof538
538GCK
c683CT
p(Th
r228Met)
M9
1Diet
None
NA
Mother
173NA
NA
KnownMODY
Siblin
gof537
543GCK
c184GA
p(V
al62Met)
M4
02Diet
None
NA
Mother
NA
NA
NA
KnownMODY
Siblin
gof544
544GCK
c184GA
p(V
al62Met)
M3
2Diet
None
NA
Mother
NA
NA
NA
KnownMODY
Siblin
gof543
1396GCK
c1209del
p(Ile404fs)
M14
03Diet
None
71stMother
NA
NA
NA
KnownMODY
8002095GCK
c1019GT
p(Ser340Ile)
M9
5Diet
None
88thFath
er079
Neg
NA
KnownMODY
8002372GCK
c1340GA
p(A
rg447Gln)
M18
06Diet
None
90thNeith
erNottested
Neg
Nottested
New
lyiden
tified
MODY
599HNF1A
c608GA
p(A
rg203His)
F14
05OHA
OHA
99thBoth
paren
ts308
Neg
Neg
KnownMODY
1012HNF1A
c872del
p(Pro
291fs)F
1007
Diet
Diet
99thMother
56Neg
Neg
KnownMODY
Siblin
gof395
395HNF1A
c872del
p(Pro
291fs)F
1401
OHA
OHA
95thMother
58Neg
Neg
KnownMODY
Siblin
gof1012
455HNF1A
c872dup
p(G
ly292fs)F
123
OHA
OHA
57thFath
er086
Neg
Neg
KnownMODY
567HNF1A
c872dup
p(G
ly292fs)M
82
Diet
OHA
94thMother
173Neg
Neg
KnownMODY
686HNF4A
c749TC
p(Leu
250Pro)
M16
07Diet
Diet
99thFath
er474
NA
NA
KnownMODY
1348HNF4A
c340CT
p(A
rg114Trp)
F15
02Insulin
OHA
86thFath
er300
Neg
Neg
New
lyiden
tified
MODY
1203HNF4A
c340CT
p(A
rg114Trp)
M7
2Insulin
Insulin
39thNeith
er021
Neg
Neg
Duald
iagnosis
new
lyiden
tified
HNF4A
knowntyp
e1diab
etes
377HNF4A
c-12GA
p()
F11
2Insulin
Insulin
99thMother
028Neg
Neg
New
lyiden
tified
MODY
854HNF1B
c1-_151+d
elp(0)
(whole
genedeletio
n)
M11
2Insulin
Insulin
9thFath
er071
Neg
Neg
New
lyiden
tified
MODY
555ABCC8
c4139GA
p(A
rg1380His)
F11
8OHA
OHA
4thFath
er300
Neg
Neg
KnownMODY
758INSR
c3706CG
p(P
ro1236A
la)F
123
OHA
Diet
55thMother
907NA
NA
KnownMODY
Ffemale
IDid
entifi
cationMm
aleNAn
otapplicab
legenetic
diagn
osis
mad
eprio
rto
studyNegn
egativeOHAo
ralhypoglycem
icagen
tG
ADnegativede
finedinthis
studyas
99th
percentilebutGAD259
(975thpercentile)M
utations
aredescribed
usingthe
Hum
anGenom
eVariation
Societynom
enclatureguidelines
according
tothe
following
referencesequ
encesG
CKNM_0001623H
NF1A
NM_0005456H
NF4A
NM_1759144A
BCC8
NM_0012871741IN
SRNM_0002082D
iabetes
duratio
nat
timeofstu
dy
carediabetesjournalsorg Shepherd and Associates 1885
diabetes or lack of insulin therapy andHbA1c levels of 75 (58 mmolmol)The lower prevalence (11) probably re-flected that they studied children 0ndash14years of age rather than 0ndash20 years ofage (mean age at diagnosis in our study106 years) and only 10 patients weretested for GCK The US study (119) likeour study used systematic biomarkerscreening with genetic testing performedin all patients who had measurableC-peptide levels and did not have GADand IA2 autoantibodies The lower preva-lence in their cohort probably results fromnon-MODY patients having more ldquotype2 featuresrdquo suggesting a greater propor-tion of patients with young-onset type 2diabetes because the combined preva-lence of MODY in minority individuals wasvery similar to the prevalence of MODY innon-Hispanic white individuals (1) Therearemany other less comprehensive studies(252730) of the prevalence of monogenicdiabetes (Table 1) these are limited bystudying a single clinic using a nonsystem-atic assessment andor not making arobust molecular genetic diagnosis (con-firmed mutations not polymorphisms)Our study indicated a higher propor-
tion of known cases of MODY versusnew cases identified through systematicscreening The 28 patients with previ-ously confirmed MODY (15 who tookpart and 13 who did not take part inthe study) reflect the high levels ofawareness of monogenic diabetes inthese geographical regions The 13 pa-tients previously identified who did nottake part in the study included 9 withGCK MODY (who had been dischargedfrom clinic follow-up) 3 with HNF1AMODY and 1 with Wolfram syndromeThis study shows that clinical recognitionof key phenotypes in patients and theirfamily members can identify the major-ity of pediatric patients (15 of 20 inthis study) However the five new pa-tients identified through this pathwayof screening indicate the need for a sys-tematic approach If this approach wereused in other areas where the recogni-tion of monogenic diabetes is not so ap-parent then a greater proportion of newcases would be identified We havebased our prevalence figures only onthe population recruited in this studyhowever if the 13 patients who did nottake part were taken into account thiscould give a prevalence as high as 33(33 of 1016 patients) There are estimated
to be35000 children and young peoplewith diabetes who are under 19 yearsof age in the UK (3132) If the preva-lence of 25 found in those patientswho took part in this six-clinic surveyreflects the whole of the UK then thissuggests at least 875 expected patientswith MODY in this age group (95CI 560ndash1365) of whom 468 havereceived a diagnosis to date with50 still likely to be misdiagnosedas having type 1 diabetes
This approach of systematic testingcombined with clinical criteria can resultin a diagnosis in 99 of patients andthis is an advantage of this approach be-yond the recognition of monogenic diabe-tes We were able to use C-peptideautoantibody and genetic testing togive a clear diagnosis in 923 of patientsClinical criteria suggest that 33 hadtype 2 diabetes a figure that is very similarto the number of individuals with mono-genic diabetes as seen in other Europeanpopulations (72433) A total of 02 hadsecondary diabetes due to cystic fibrosiswhich probably reflects an underestimateasmanyof these patientswill not attend apediatric diabetes clinic A further 32were within 3 years of having received adiagnosis and probably had antibody-negative type 1 diabetes in the honey-moonperiod There remainedfivepatients(06) who were atypical and hard toclassifydthey may represent atypicaltype 1 diabetes (antibody negative andsignificant C-peptide levels3 years afterdiagnosis) or a presently unrecognizedsubtype of monogenic diabetes
There were limitations to this studyThe geographical areas where the studywas undertaken already had a highawareness of MODY so the number ofnew cases was low (25) relative tothose already known (75) while else-where in the UK we estimate that thisfigure is50 detected and 50 unde-tected We subjected only those pa-tients who had significant endogenousinsulin (C-peptide) levels and did nothave autoantibodies to systematic genetictesting although previous research(141718) and our failure to find anymu-tations in 65 patients who did have sig-nificant C-peptide levels but wereantibody positive support the idea thatthis approach wouldmiss very few casesUCPCR calculation was performed irre-spective of the duration of diabetesand it is acknowledged that some of
the patients tested close to receiving adiagnosis could be producing endoge-nous insulin during the honeymoon pe-riod and if retested over time thatthose patients with type 1 diabeteswould be expected to have decliningC-peptide levels The calculation of UCPCRis best for excluding patients 3 yearsafter diabetes is diagnosed while au-toantibody testing is best for excludingpatients close to diagnosis In thisstudy we wanted to test everyone re-gardless of disease duration so a test-ing method that used both biomarkersworked well If a study was performed ofpurely incident cases which would havean advantage of making the correct di-agnosis early then measuring C-peptidelevels would have little value and furthertesting could be performed on those in-dividuals who had negative results fromtesting for multiple autoantibodies Al-though patients were asked to send aldquopostmealrdquo urine sample the prandialstate of the patient was assumed (andnot observed) therefore we cannot becertain that all UCPCR tests were stimu-lated Our population consisted predomi-nantly (96) of whites and systematicstudies in other especially high-prevalencepopulations are also needed
There aremany strengths of this studyThe result is likely to be representative ofthe clinics studied because 795 of theeligible population took part a result thatshows the high acceptability of this ap-proach in pediatric clinics The systematicbiomarkerndashbased approach that is inde-pendent of clinical features allows atypi-cal patients to be detected (eg thosewith no family history of diabetes) Thisis the first study that has used next-generation sequencing to assess allknown causes of monogenic diabetes al-though themajority of patients (85) hadthe most common types of MODY (GCKHNF1A and HNF4A) so studies that havenot used this approach will have missedonly a few patients
This systematic high-uptake studygives a prevalence of 25 (95 CI 16ndash39) for monogenic diabetes in the UKpediatric population Patients with mono-genic diabetes were identified in everypediatric clinic The successful identifica-tion of patients with monogenic diabe-tes is crucial because they requiredifferent treatment than those withtype 1 or type 2 diabetes The vast major-ity (99) of pediatric patients can be
1886 UK Screening for Pediatric Monogenic Diabetes Diabetes Care Volume 39 November 2016
successfully classified by UCPCR antibodytesting genetic testing and clinical crite-ria UCPCR is a noninvasive and inexpen-sive test which could be more widelyused in the pediatric age group whereit has a high acceptability This screeningalgorithm is a practical approach to de-termining the prevalence of cases in aclinic to ensure the correct diagnosis ofsubtypes of diabetes Confirming a prev-alence of MODY of 25 in the pediatricpopulation indicates that all those in-volved in pediatric diabetes care shouldbe aware of the possibility of an alterna-tive diagnosis and know how to referpatients for genetic testing
Acknowledgments The authors thank the pa-tientswhotookpartinthisstudyandthenurseswhorecruited them for their support with this projectFunding This work presents independent re-search commissioned by the Health InnovationChallenge Fund a parallel funding partnershipbetween theWellcome Trust and the DepartmentofHealth(grantHICF-1009-041)andwassupportedbytheNational Institute forHealthResearch (NIHR)ExeterClinicalResearchFacility and theSouthWestPeninsula Diabetes Research Network MS issupported by the NIHR Exeter Clinical ResearchFacilityTJM is fundedbyanNIHRCSOFellowshipSE and ATH are both Wellcome Trust SeniorInvestigators ERP is a Wellcome Trust New In-vestigator ATH is an NIHR Senior InvestigatorTheviewsexpressed in thispublicationare those
of the authors and not necessarily those of theWellcomeTrust theNHS theNational Institute forHealth Research or the Department of HealthDuality of Interest No potential conflicts ofinterest relevant to this article were reportedAuthor Contributions MS wrote the manu-script and collected and analyzed the data BSanalyzed the data and reviewed and editedthe manuscript SH collected the data andreviewed the manuscript MH coordinatedthe project assistedwith the data and reviewedthe manuscript TJM coordinated the urinaryC-peptide creatinine ratio determination andantibody testing and reviewed the manuscriptKC assistedwith genetic data and reviewed andedited themanuscript RAO contributed to thediscussion and reviewed the manuscript BKdeveloped the protocol submitted the ethicsapplication and reviewed the manuscript CHreviewed the manuscript JC KM CM RSBF SR andSG facilitatedpatient recruitmentwithin their pediatric clinics and reviewed themanuscript SE coordinated the genetic testingand reviewed the manuscript ERP coordi-nated the Tayside arm of the project and re-viewed and edited the manuscript ATHdesigned the study contributed to the discus-sion and reviewed and edited the manuscriptThe UNITED team collected the data MS is theguarantor of this work and as such had fullaccess to all the data in the study and takesresponsibility for the integrity of the data andthe accuracy of the data analysis
References1 Pihoker C Gilliam LK Ellard S et al SEARCHfor Diabetes in Youth Study Group Preva-lence characteristics and clinical diagnosis ofmaturity onset diabetes of the young due to mu-tations inHNF1A HNF4A and glucokinase resultsfrom the SEARCH for Diabetes in Youth J ClinEndocrinol Metab 2013984055ndash40622 Irgens HU Molnes J Johansson BB et al Prev-alence of monogenic diabetes in the population-based Norwegian Childhood Diabetes RegistryDiabetologia 2013561512ndash15193 Carmody D Lindauer KL Naylor RN Adoles-cent non-adherence reveals a genetic cause fordiabetes Diabet Med 201532e20ndashe234 Gandica RG Chung WK Deng L Goland RGallagher MP Identifying monogenic diabetesin a pediatric cohort with presumed type 1 di-abetes Pediatr Diabetes 201516227ndash2335 Lambert AP Ellard S Allen LI et al Identify-ing hepatic nuclear factor 1alpha mutations inchildren and young adults with a clinical diag-nosis of type 1 diabetes Diabetes Care 200326333ndash3376 Thirumalai A Holing E Brown Z Gilliam LK Acase of hepatocyte nuclear factor-1b (TCF2) ma-turity onset diabetes of the youngmisdiagnosedas type 1 diabetes and treated unnecessarilywith insulin J Diabetes 20135462ndash4647 Fendler W Borowiec M Baranowska-Jazwiecka A et al Prevalence of monogenicdiabetes amongst Polish children after a nation-wide genetic screening campaign Diabetologia2012552631ndash26358 Rubio-Cabezas O Edghill EL Argente JHattersley AT Testing for monogenic diabetesamong children and adolescents with antibody-negative clinically defined type 1 diabetes Dia-bet Med 2009261070ndash10749 Murphy R Ellard S Hattersley AT Clinicalimplications of a molecular genetic classifica-tion of monogenic beta-cell diabetes Nat ClinPract Endocrinol Metab 20084200ndash21310 Rubio-Cabezas O Hattersley AT NjoslashlstadPR et al International Society for Pediatricand Adolescent Diabetes ISPAD Clinical PracticeConsensus Guidelines 2014 The diagnosis andmanagement of monogenic diabetes in childrenand adolescents Pediatr Diabetes 201415(Suppl 20)47ndash6411 Craig ME Jefferies C Dabelea D Balde NSeth A Donaghue KC International Societyfor Pediatric and Adolescent Diabetes ISPADClinical Practice Consensus Guidelines 2014Definition epidemiology and classification ofdiabetes in children and adolescents PediatrDiabetes 201415(Suppl 20)4ndash1712 Colclough K Saint-Martin C Timsit J EllardS Bellanne-Chantelot C Clinical utility gene cardfor maturity-onset diabetes of the young Eur JHum Genet 12 February 2014 [Epub ahead ofprint] DOI 101038ejhg20141413 Shields BM Hicks S Shepherd MHColclough K Hattersley AT Ellard S Maturity-onset diabetes of the young (MODY) howmanycases are we missing Diabetologia 2010532504ndash250814 Besser RE Shepherd MH McDonald TJet al Urinary C-peptide creatinine ratio is apractical outpatient tool for identifying hepato-cyte nuclear factor 1-alphahepatocyte nuclearfactor 4-alpha maturity-onset diabetes of the
young from long-duration type 1 diabetes Di-abetes Care 201134286ndash29115 McDonald TJ Knight BA Shields BMBowman P Salzmann MB Hattersley AT Stabil-ity and reproducibility of a single-sample urinaryC-peptidecreatinine ratio and its correlation with24-h urinary C-peptide Clin Chem 2009552035ndash203916 Besser RE Ludvigsson J Jones AG et alUrine C-peptide creatinine ratio is a noninvasivealternative to the mixed-meal tolerance test inchildren and adults with type 1 diabetes Diabe-tes Care 201134607ndash60917 Besser RE Shields BM Hammersley SEet al Home urine C-peptide creatinine ratio(UCPCR) testing can identify type 2 and MODYin pediatric diabetes Pediatr Diabetes 201314181ndash18818 McDonald TJ Colclough K Brown R et alIslet autoantibodies can discriminate maturity-onset diabetes of the young (MODY) from type 1diabetes Diabet Med 2011281028ndash103319 Kanakatti Shankar R Pihoker C Dolan LMet al SEARCH for Diabetes in Youth Study GroupPermanent neonatal diabetes mellitus preva-lence and genetic diagnosis in the SEARCH for Di-abetes in Youth Study Pediatr Diabetes 201314174ndash18020 Hameed S Ellard S Woodhead HJ et alPersistently autoantibody negative (PAN)type 1 diabetes mellitus in children Pediatr Di-abetes 201112142ndash14921 Wheeler BJ Patterson N Love DR et alFrequency and genetic spectrum of maturity-onset diabetes of the young (MODY) in southernNew Zealand J Diabetes Metab Disord 2013124622 Redondo MJ Rodriguez LM Escalante MSmith EO Balasubramanyam A HaymondMW Types of pediatric diabetes mellitus de-fined by anti-islet autoimmunity and randomC-peptide at diagnosis Pediatr Diabetes 201314333ndash34023 Ehtisham S Hattersley AT Dunger DBBarrett TG British Society for Paediatric Endo-crinology and Diabetes Clinical Trials GroupFirst UK survey of paediatric type 2 diabetesand MODY Arch Dis Child 200489526ndash52924 Neu A Feldhahn L Ehehalt S Hub R RankeMB DIARY group Baden-Wurttemberg Type2 diabetes mellitus in children and adolescentsis still a rare disease in Germany a population-based assessment of the prevalence of type 2diabetes and MODY in patients aged 0-20 yearsPediatr Diabetes 200910468ndash47325 Amed S Dean HJ Panagiotopoulos C et alType 2 diabetes medication-induced diabetesand monogenic diabetes in Canadian children aprospective national surveillance study Diabe-tes Care 201033786ndash79126 Galler A Stange T Muller G et al Child-hood Diabetes Registry in Saxony Germany In-cidence of childhood diabetes in children agedless than 15 years and its clinical and metaboliccharacteristics at the time of diagnosis datafrom the Childhood Diabetes Registry of Sax-ony Germany Horm Res Paediatr 201074285ndash29127 Schober E Rami B Grabert M et al DPV-Wiss Initiative of the GermanWorking Group forPaediatric Diabetology and Phenotypical as-pects of maturity-onset diabetes of the young
carediabetesjournalsorg Shepherd and Associates 1887
(MODY diabetes) in comparison with type 2 di-abetes mellitus (T2DM) in children and adoles-cents experience from a large multicentredatabase Diabet Med 200926466ndash47328 Freeman JV Cole TJ Chinn S et al Crosssectional stature and weight reference curvesfor the UK 1990 Arch Dis Child 19957317ndash2429 Ellard S Lango Allen H De Franco E et alImproved genetic testing for monogenic diabe-tes using targeted next-generation sequencingDiabetologia 2013561958ndash196330 Awa WL Thon A Raile K et al DPV-WissStudy Group Genetic and clinical characteristicsof patients with HNF1A gene variations from the
German-Austrian DPV database Eur J Endocri-nol 2011164513ndash52031 Health amp Social Care Information CentreNational diabetes audit 2011-12 report 1 careprocesses and treatment targets CCG and LHGdata tables [Internet] 2013 Available fromhttpwwwhscicgovuksearchcatalogueproductid=13129ampq=22National+diabetes+audit22ampsort=Relevanceampsize=10amppage=1top Ac-cessed 3 January 201632 Diabetes in Scotland Scottish Diabetes Sur-vey 2014 [Internet] 2014 Available from httpwwwdiabetesinscotlandorgukPublicationsSDS2014pdf Accessed 3 January 2016
33 Vaziri-Sani F Delli AJ Elding-Larsson Het al A novel triple mix radiobinding assay forthe three ZnT8 (ZnT8-RWQ) autoantibody vari-ants in children with newly diagnosed diabetesJ Immunol Methods 201137125ndash3734 Yorifuji T Fujimaru R Hosokawa Y et alComprehensive molecular analysis of Japa-nese patients with pediatric-onset MODY-type diabetes mellitus Pediatr Diabetes20121326ndash3235 Chambers C Fouts A Dong F et al Charac-teristics of maturity onset diabetes of the youngin a large diabetes center Pediatr Diabetes201617360ndash367
1888 UK Screening for Pediatric Monogenic Diabetes Diabetes Care Volume 39 November 2016
Table
2mdashCharacte
risticsofth
e20patie
nts
identifi
edwith
monogenic
diabetes
StudyID
Gen
eMutatio
n
Protein
effectGen
der
Age
atdiagn
osis
(years)
Diab
etesduratio
n(years)
Initial
treatmen
tCurren
ttreatm
ent
BMI
percen
tileAffectedparen
t
UCPCR
(nmol
mmol)
GAD
IA2
Notes
211GCK
c97_117dup
p(V
al33_Lys39dup)
M3
13Insulin
None
99thMother
357NA
NA
KnownMODY
537GCK
c683CT
p(Th
r228Met)
M11
2Diet
None
NA
Mother
194NA
NA
KnownMODY
Siblin
gof538
538GCK
c683CT
p(Th
r228Met)
M9
1Diet
None
NA
Mother
173NA
NA
KnownMODY
Siblin
gof537
543GCK
c184GA
p(V
al62Met)
M4
02Diet
None
NA
Mother
NA
NA
NA
KnownMODY
Siblin
gof544
544GCK
c184GA
p(V
al62Met)
M3
2Diet
None
NA
Mother
NA
NA
NA
KnownMODY
Siblin
gof543
1396GCK
c1209del
p(Ile404fs)
M14
03Diet
None
71stMother
NA
NA
NA
KnownMODY
8002095GCK
c1019GT
p(Ser340Ile)
M9
5Diet
None
88thFath
er079
Neg
NA
KnownMODY
8002372GCK
c1340GA
p(A
rg447Gln)
M18
06Diet
None
90thNeith
erNottested
Neg
Nottested
New
lyiden
tified
MODY
599HNF1A
c608GA
p(A
rg203His)
F14
05OHA
OHA
99thBoth
paren
ts308
Neg
Neg
KnownMODY
1012HNF1A
c872del
p(Pro
291fs)F
1007
Diet
Diet
99thMother
56Neg
Neg
KnownMODY
Siblin
gof395
395HNF1A
c872del
p(Pro
291fs)F
1401
OHA
OHA
95thMother
58Neg
Neg
KnownMODY
Siblin
gof1012
455HNF1A
c872dup
p(G
ly292fs)F
123
OHA
OHA
57thFath
er086
Neg
Neg
KnownMODY
567HNF1A
c872dup
p(G
ly292fs)M
82
Diet
OHA
94thMother
173Neg
Neg
KnownMODY
686HNF4A
c749TC
p(Leu
250Pro)
M16
07Diet
Diet
99thFath
er474
NA
NA
KnownMODY
1348HNF4A
c340CT
p(A
rg114Trp)
F15
02Insulin
OHA
86thFath
er300
Neg
Neg
New
lyiden
tified
MODY
1203HNF4A
c340CT
p(A
rg114Trp)
M7
2Insulin
Insulin
39thNeith
er021
Neg
Neg
Duald
iagnosis
new
lyiden
tified
HNF4A
knowntyp
e1diab
etes
377HNF4A
c-12GA
p()
F11
2Insulin
Insulin
99thMother
028Neg
Neg
New
lyiden
tified
MODY
854HNF1B
c1-_151+d
elp(0)
(whole
genedeletio
n)
M11
2Insulin
Insulin
9thFath
er071
Neg
Neg
New
lyiden
tified
MODY
555ABCC8
c4139GA
p(A
rg1380His)
F11
8OHA
OHA
4thFath
er300
Neg
Neg
KnownMODY
758INSR
c3706CG
p(P
ro1236A
la)F
123
OHA
Diet
55thMother
907NA
NA
KnownMODY
Ffemale
IDid
entifi
cationMm
aleNAn
otapplicab
legenetic
diagn
osis
mad
eprio
rto
studyNegn
egativeOHAo
ralhypoglycem
icagen
tG
ADnegativede
finedinthis
studyas
99th
percentilebutGAD259
(975thpercentile)M
utations
aredescribed
usingthe
Hum
anGenom
eVariation
Societynom
enclatureguidelines
according
tothe
following
referencesequ
encesG
CKNM_0001623H
NF1A
NM_0005456H
NF4A
NM_1759144A
BCC8
NM_0012871741IN
SRNM_0002082D
iabetes
duratio
nat
timeofstu
dy
carediabetesjournalsorg Shepherd and Associates 1885
diabetes or lack of insulin therapy andHbA1c levels of 75 (58 mmolmol)The lower prevalence (11) probably re-flected that they studied children 0ndash14years of age rather than 0ndash20 years ofage (mean age at diagnosis in our study106 years) and only 10 patients weretested for GCK The US study (119) likeour study used systematic biomarkerscreening with genetic testing performedin all patients who had measurableC-peptide levels and did not have GADand IA2 autoantibodies The lower preva-lence in their cohort probably results fromnon-MODY patients having more ldquotype2 featuresrdquo suggesting a greater propor-tion of patients with young-onset type 2diabetes because the combined preva-lence of MODY in minority individuals wasvery similar to the prevalence of MODY innon-Hispanic white individuals (1) Therearemany other less comprehensive studies(252730) of the prevalence of monogenicdiabetes (Table 1) these are limited bystudying a single clinic using a nonsystem-atic assessment andor not making arobust molecular genetic diagnosis (con-firmed mutations not polymorphisms)Our study indicated a higher propor-
tion of known cases of MODY versusnew cases identified through systematicscreening The 28 patients with previ-ously confirmed MODY (15 who tookpart and 13 who did not take part inthe study) reflect the high levels ofawareness of monogenic diabetes inthese geographical regions The 13 pa-tients previously identified who did nottake part in the study included 9 withGCK MODY (who had been dischargedfrom clinic follow-up) 3 with HNF1AMODY and 1 with Wolfram syndromeThis study shows that clinical recognitionof key phenotypes in patients and theirfamily members can identify the major-ity of pediatric patients (15 of 20 inthis study) However the five new pa-tients identified through this pathwayof screening indicate the need for a sys-tematic approach If this approach wereused in other areas where the recogni-tion of monogenic diabetes is not so ap-parent then a greater proportion of newcases would be identified We havebased our prevalence figures only onthe population recruited in this studyhowever if the 13 patients who did nottake part were taken into account thiscould give a prevalence as high as 33(33 of 1016 patients) There are estimated
to be35000 children and young peoplewith diabetes who are under 19 yearsof age in the UK (3132) If the preva-lence of 25 found in those patientswho took part in this six-clinic surveyreflects the whole of the UK then thissuggests at least 875 expected patientswith MODY in this age group (95CI 560ndash1365) of whom 468 havereceived a diagnosis to date with50 still likely to be misdiagnosedas having type 1 diabetes
This approach of systematic testingcombined with clinical criteria can resultin a diagnosis in 99 of patients andthis is an advantage of this approach be-yond the recognition of monogenic diabe-tes We were able to use C-peptideautoantibody and genetic testing togive a clear diagnosis in 923 of patientsClinical criteria suggest that 33 hadtype 2 diabetes a figure that is very similarto the number of individuals with mono-genic diabetes as seen in other Europeanpopulations (72433) A total of 02 hadsecondary diabetes due to cystic fibrosiswhich probably reflects an underestimateasmanyof these patientswill not attend apediatric diabetes clinic A further 32were within 3 years of having received adiagnosis and probably had antibody-negative type 1 diabetes in the honey-moonperiod There remainedfivepatients(06) who were atypical and hard toclassifydthey may represent atypicaltype 1 diabetes (antibody negative andsignificant C-peptide levels3 years afterdiagnosis) or a presently unrecognizedsubtype of monogenic diabetes
There were limitations to this studyThe geographical areas where the studywas undertaken already had a highawareness of MODY so the number ofnew cases was low (25) relative tothose already known (75) while else-where in the UK we estimate that thisfigure is50 detected and 50 unde-tected We subjected only those pa-tients who had significant endogenousinsulin (C-peptide) levels and did nothave autoantibodies to systematic genetictesting although previous research(141718) and our failure to find anymu-tations in 65 patients who did have sig-nificant C-peptide levels but wereantibody positive support the idea thatthis approach wouldmiss very few casesUCPCR calculation was performed irre-spective of the duration of diabetesand it is acknowledged that some of
the patients tested close to receiving adiagnosis could be producing endoge-nous insulin during the honeymoon pe-riod and if retested over time thatthose patients with type 1 diabeteswould be expected to have decliningC-peptide levels The calculation of UCPCRis best for excluding patients 3 yearsafter diabetes is diagnosed while au-toantibody testing is best for excludingpatients close to diagnosis In thisstudy we wanted to test everyone re-gardless of disease duration so a test-ing method that used both biomarkersworked well If a study was performed ofpurely incident cases which would havean advantage of making the correct di-agnosis early then measuring C-peptidelevels would have little value and furthertesting could be performed on those in-dividuals who had negative results fromtesting for multiple autoantibodies Al-though patients were asked to send aldquopostmealrdquo urine sample the prandialstate of the patient was assumed (andnot observed) therefore we cannot becertain that all UCPCR tests were stimu-lated Our population consisted predomi-nantly (96) of whites and systematicstudies in other especially high-prevalencepopulations are also needed
There aremany strengths of this studyThe result is likely to be representative ofthe clinics studied because 795 of theeligible population took part a result thatshows the high acceptability of this ap-proach in pediatric clinics The systematicbiomarkerndashbased approach that is inde-pendent of clinical features allows atypi-cal patients to be detected (eg thosewith no family history of diabetes) Thisis the first study that has used next-generation sequencing to assess allknown causes of monogenic diabetes al-though themajority of patients (85) hadthe most common types of MODY (GCKHNF1A and HNF4A) so studies that havenot used this approach will have missedonly a few patients
This systematic high-uptake studygives a prevalence of 25 (95 CI 16ndash39) for monogenic diabetes in the UKpediatric population Patients with mono-genic diabetes were identified in everypediatric clinic The successful identifica-tion of patients with monogenic diabe-tes is crucial because they requiredifferent treatment than those withtype 1 or type 2 diabetes The vast major-ity (99) of pediatric patients can be
1886 UK Screening for Pediatric Monogenic Diabetes Diabetes Care Volume 39 November 2016
successfully classified by UCPCR antibodytesting genetic testing and clinical crite-ria UCPCR is a noninvasive and inexpen-sive test which could be more widelyused in the pediatric age group whereit has a high acceptability This screeningalgorithm is a practical approach to de-termining the prevalence of cases in aclinic to ensure the correct diagnosis ofsubtypes of diabetes Confirming a prev-alence of MODY of 25 in the pediatricpopulation indicates that all those in-volved in pediatric diabetes care shouldbe aware of the possibility of an alterna-tive diagnosis and know how to referpatients for genetic testing
Acknowledgments The authors thank the pa-tientswhotookpartinthisstudyandthenurseswhorecruited them for their support with this projectFunding This work presents independent re-search commissioned by the Health InnovationChallenge Fund a parallel funding partnershipbetween theWellcome Trust and the DepartmentofHealth(grantHICF-1009-041)andwassupportedbytheNational Institute forHealthResearch (NIHR)ExeterClinicalResearchFacility and theSouthWestPeninsula Diabetes Research Network MS issupported by the NIHR Exeter Clinical ResearchFacilityTJM is fundedbyanNIHRCSOFellowshipSE and ATH are both Wellcome Trust SeniorInvestigators ERP is a Wellcome Trust New In-vestigator ATH is an NIHR Senior InvestigatorTheviewsexpressed in thispublicationare those
of the authors and not necessarily those of theWellcomeTrust theNHS theNational Institute forHealth Research or the Department of HealthDuality of Interest No potential conflicts ofinterest relevant to this article were reportedAuthor Contributions MS wrote the manu-script and collected and analyzed the data BSanalyzed the data and reviewed and editedthe manuscript SH collected the data andreviewed the manuscript MH coordinatedthe project assistedwith the data and reviewedthe manuscript TJM coordinated the urinaryC-peptide creatinine ratio determination andantibody testing and reviewed the manuscriptKC assistedwith genetic data and reviewed andedited themanuscript RAO contributed to thediscussion and reviewed the manuscript BKdeveloped the protocol submitted the ethicsapplication and reviewed the manuscript CHreviewed the manuscript JC KM CM RSBF SR andSG facilitatedpatient recruitmentwithin their pediatric clinics and reviewed themanuscript SE coordinated the genetic testingand reviewed the manuscript ERP coordi-nated the Tayside arm of the project and re-viewed and edited the manuscript ATHdesigned the study contributed to the discus-sion and reviewed and edited the manuscriptThe UNITED team collected the data MS is theguarantor of this work and as such had fullaccess to all the data in the study and takesresponsibility for the integrity of the data andthe accuracy of the data analysis
References1 Pihoker C Gilliam LK Ellard S et al SEARCHfor Diabetes in Youth Study Group Preva-lence characteristics and clinical diagnosis ofmaturity onset diabetes of the young due to mu-tations inHNF1A HNF4A and glucokinase resultsfrom the SEARCH for Diabetes in Youth J ClinEndocrinol Metab 2013984055ndash40622 Irgens HU Molnes J Johansson BB et al Prev-alence of monogenic diabetes in the population-based Norwegian Childhood Diabetes RegistryDiabetologia 2013561512ndash15193 Carmody D Lindauer KL Naylor RN Adoles-cent non-adherence reveals a genetic cause fordiabetes Diabet Med 201532e20ndashe234 Gandica RG Chung WK Deng L Goland RGallagher MP Identifying monogenic diabetesin a pediatric cohort with presumed type 1 di-abetes Pediatr Diabetes 201516227ndash2335 Lambert AP Ellard S Allen LI et al Identify-ing hepatic nuclear factor 1alpha mutations inchildren and young adults with a clinical diag-nosis of type 1 diabetes Diabetes Care 200326333ndash3376 Thirumalai A Holing E Brown Z Gilliam LK Acase of hepatocyte nuclear factor-1b (TCF2) ma-turity onset diabetes of the youngmisdiagnosedas type 1 diabetes and treated unnecessarilywith insulin J Diabetes 20135462ndash4647 Fendler W Borowiec M Baranowska-Jazwiecka A et al Prevalence of monogenicdiabetes amongst Polish children after a nation-wide genetic screening campaign Diabetologia2012552631ndash26358 Rubio-Cabezas O Edghill EL Argente JHattersley AT Testing for monogenic diabetesamong children and adolescents with antibody-negative clinically defined type 1 diabetes Dia-bet Med 2009261070ndash10749 Murphy R Ellard S Hattersley AT Clinicalimplications of a molecular genetic classifica-tion of monogenic beta-cell diabetes Nat ClinPract Endocrinol Metab 20084200ndash21310 Rubio-Cabezas O Hattersley AT NjoslashlstadPR et al International Society for Pediatricand Adolescent Diabetes ISPAD Clinical PracticeConsensus Guidelines 2014 The diagnosis andmanagement of monogenic diabetes in childrenand adolescents Pediatr Diabetes 201415(Suppl 20)47ndash6411 Craig ME Jefferies C Dabelea D Balde NSeth A Donaghue KC International Societyfor Pediatric and Adolescent Diabetes ISPADClinical Practice Consensus Guidelines 2014Definition epidemiology and classification ofdiabetes in children and adolescents PediatrDiabetes 201415(Suppl 20)4ndash1712 Colclough K Saint-Martin C Timsit J EllardS Bellanne-Chantelot C Clinical utility gene cardfor maturity-onset diabetes of the young Eur JHum Genet 12 February 2014 [Epub ahead ofprint] DOI 101038ejhg20141413 Shields BM Hicks S Shepherd MHColclough K Hattersley AT Ellard S Maturity-onset diabetes of the young (MODY) howmanycases are we missing Diabetologia 2010532504ndash250814 Besser RE Shepherd MH McDonald TJet al Urinary C-peptide creatinine ratio is apractical outpatient tool for identifying hepato-cyte nuclear factor 1-alphahepatocyte nuclearfactor 4-alpha maturity-onset diabetes of the
young from long-duration type 1 diabetes Di-abetes Care 201134286ndash29115 McDonald TJ Knight BA Shields BMBowman P Salzmann MB Hattersley AT Stabil-ity and reproducibility of a single-sample urinaryC-peptidecreatinine ratio and its correlation with24-h urinary C-peptide Clin Chem 2009552035ndash203916 Besser RE Ludvigsson J Jones AG et alUrine C-peptide creatinine ratio is a noninvasivealternative to the mixed-meal tolerance test inchildren and adults with type 1 diabetes Diabe-tes Care 201134607ndash60917 Besser RE Shields BM Hammersley SEet al Home urine C-peptide creatinine ratio(UCPCR) testing can identify type 2 and MODYin pediatric diabetes Pediatr Diabetes 201314181ndash18818 McDonald TJ Colclough K Brown R et alIslet autoantibodies can discriminate maturity-onset diabetes of the young (MODY) from type 1diabetes Diabet Med 2011281028ndash103319 Kanakatti Shankar R Pihoker C Dolan LMet al SEARCH for Diabetes in Youth Study GroupPermanent neonatal diabetes mellitus preva-lence and genetic diagnosis in the SEARCH for Di-abetes in Youth Study Pediatr Diabetes 201314174ndash18020 Hameed S Ellard S Woodhead HJ et alPersistently autoantibody negative (PAN)type 1 diabetes mellitus in children Pediatr Di-abetes 201112142ndash14921 Wheeler BJ Patterson N Love DR et alFrequency and genetic spectrum of maturity-onset diabetes of the young (MODY) in southernNew Zealand J Diabetes Metab Disord 2013124622 Redondo MJ Rodriguez LM Escalante MSmith EO Balasubramanyam A HaymondMW Types of pediatric diabetes mellitus de-fined by anti-islet autoimmunity and randomC-peptide at diagnosis Pediatr Diabetes 201314333ndash34023 Ehtisham S Hattersley AT Dunger DBBarrett TG British Society for Paediatric Endo-crinology and Diabetes Clinical Trials GroupFirst UK survey of paediatric type 2 diabetesand MODY Arch Dis Child 200489526ndash52924 Neu A Feldhahn L Ehehalt S Hub R RankeMB DIARY group Baden-Wurttemberg Type2 diabetes mellitus in children and adolescentsis still a rare disease in Germany a population-based assessment of the prevalence of type 2diabetes and MODY in patients aged 0-20 yearsPediatr Diabetes 200910468ndash47325 Amed S Dean HJ Panagiotopoulos C et alType 2 diabetes medication-induced diabetesand monogenic diabetes in Canadian children aprospective national surveillance study Diabe-tes Care 201033786ndash79126 Galler A Stange T Muller G et al Child-hood Diabetes Registry in Saxony Germany In-cidence of childhood diabetes in children agedless than 15 years and its clinical and metaboliccharacteristics at the time of diagnosis datafrom the Childhood Diabetes Registry of Sax-ony Germany Horm Res Paediatr 201074285ndash29127 Schober E Rami B Grabert M et al DPV-Wiss Initiative of the GermanWorking Group forPaediatric Diabetology and Phenotypical as-pects of maturity-onset diabetes of the young
carediabetesjournalsorg Shepherd and Associates 1887
(MODY diabetes) in comparison with type 2 di-abetes mellitus (T2DM) in children and adoles-cents experience from a large multicentredatabase Diabet Med 200926466ndash47328 Freeman JV Cole TJ Chinn S et al Crosssectional stature and weight reference curvesfor the UK 1990 Arch Dis Child 19957317ndash2429 Ellard S Lango Allen H De Franco E et alImproved genetic testing for monogenic diabe-tes using targeted next-generation sequencingDiabetologia 2013561958ndash196330 Awa WL Thon A Raile K et al DPV-WissStudy Group Genetic and clinical characteristicsof patients with HNF1A gene variations from the
German-Austrian DPV database Eur J Endocri-nol 2011164513ndash52031 Health amp Social Care Information CentreNational diabetes audit 2011-12 report 1 careprocesses and treatment targets CCG and LHGdata tables [Internet] 2013 Available fromhttpwwwhscicgovuksearchcatalogueproductid=13129ampq=22National+diabetes+audit22ampsort=Relevanceampsize=10amppage=1top Ac-cessed 3 January 201632 Diabetes in Scotland Scottish Diabetes Sur-vey 2014 [Internet] 2014 Available from httpwwwdiabetesinscotlandorgukPublicationsSDS2014pdf Accessed 3 January 2016
33 Vaziri-Sani F Delli AJ Elding-Larsson Het al A novel triple mix radiobinding assay forthe three ZnT8 (ZnT8-RWQ) autoantibody vari-ants in children with newly diagnosed diabetesJ Immunol Methods 201137125ndash3734 Yorifuji T Fujimaru R Hosokawa Y et alComprehensive molecular analysis of Japa-nese patients with pediatric-onset MODY-type diabetes mellitus Pediatr Diabetes20121326ndash3235 Chambers C Fouts A Dong F et al Charac-teristics of maturity onset diabetes of the youngin a large diabetes center Pediatr Diabetes201617360ndash367
1888 UK Screening for Pediatric Monogenic Diabetes Diabetes Care Volume 39 November 2016
diabetes or lack of insulin therapy andHbA1c levels of 75 (58 mmolmol)The lower prevalence (11) probably re-flected that they studied children 0ndash14years of age rather than 0ndash20 years ofage (mean age at diagnosis in our study106 years) and only 10 patients weretested for GCK The US study (119) likeour study used systematic biomarkerscreening with genetic testing performedin all patients who had measurableC-peptide levels and did not have GADand IA2 autoantibodies The lower preva-lence in their cohort probably results fromnon-MODY patients having more ldquotype2 featuresrdquo suggesting a greater propor-tion of patients with young-onset type 2diabetes because the combined preva-lence of MODY in minority individuals wasvery similar to the prevalence of MODY innon-Hispanic white individuals (1) Therearemany other less comprehensive studies(252730) of the prevalence of monogenicdiabetes (Table 1) these are limited bystudying a single clinic using a nonsystem-atic assessment andor not making arobust molecular genetic diagnosis (con-firmed mutations not polymorphisms)Our study indicated a higher propor-
tion of known cases of MODY versusnew cases identified through systematicscreening The 28 patients with previ-ously confirmed MODY (15 who tookpart and 13 who did not take part inthe study) reflect the high levels ofawareness of monogenic diabetes inthese geographical regions The 13 pa-tients previously identified who did nottake part in the study included 9 withGCK MODY (who had been dischargedfrom clinic follow-up) 3 with HNF1AMODY and 1 with Wolfram syndromeThis study shows that clinical recognitionof key phenotypes in patients and theirfamily members can identify the major-ity of pediatric patients (15 of 20 inthis study) However the five new pa-tients identified through this pathwayof screening indicate the need for a sys-tematic approach If this approach wereused in other areas where the recogni-tion of monogenic diabetes is not so ap-parent then a greater proportion of newcases would be identified We havebased our prevalence figures only onthe population recruited in this studyhowever if the 13 patients who did nottake part were taken into account thiscould give a prevalence as high as 33(33 of 1016 patients) There are estimated
to be35000 children and young peoplewith diabetes who are under 19 yearsof age in the UK (3132) If the preva-lence of 25 found in those patientswho took part in this six-clinic surveyreflects the whole of the UK then thissuggests at least 875 expected patientswith MODY in this age group (95CI 560ndash1365) of whom 468 havereceived a diagnosis to date with50 still likely to be misdiagnosedas having type 1 diabetes
This approach of systematic testingcombined with clinical criteria can resultin a diagnosis in 99 of patients andthis is an advantage of this approach be-yond the recognition of monogenic diabe-tes We were able to use C-peptideautoantibody and genetic testing togive a clear diagnosis in 923 of patientsClinical criteria suggest that 33 hadtype 2 diabetes a figure that is very similarto the number of individuals with mono-genic diabetes as seen in other Europeanpopulations (72433) A total of 02 hadsecondary diabetes due to cystic fibrosiswhich probably reflects an underestimateasmanyof these patientswill not attend apediatric diabetes clinic A further 32were within 3 years of having received adiagnosis and probably had antibody-negative type 1 diabetes in the honey-moonperiod There remainedfivepatients(06) who were atypical and hard toclassifydthey may represent atypicaltype 1 diabetes (antibody negative andsignificant C-peptide levels3 years afterdiagnosis) or a presently unrecognizedsubtype of monogenic diabetes
There were limitations to this studyThe geographical areas where the studywas undertaken already had a highawareness of MODY so the number ofnew cases was low (25) relative tothose already known (75) while else-where in the UK we estimate that thisfigure is50 detected and 50 unde-tected We subjected only those pa-tients who had significant endogenousinsulin (C-peptide) levels and did nothave autoantibodies to systematic genetictesting although previous research(141718) and our failure to find anymu-tations in 65 patients who did have sig-nificant C-peptide levels but wereantibody positive support the idea thatthis approach wouldmiss very few casesUCPCR calculation was performed irre-spective of the duration of diabetesand it is acknowledged that some of
the patients tested close to receiving adiagnosis could be producing endoge-nous insulin during the honeymoon pe-riod and if retested over time thatthose patients with type 1 diabeteswould be expected to have decliningC-peptide levels The calculation of UCPCRis best for excluding patients 3 yearsafter diabetes is diagnosed while au-toantibody testing is best for excludingpatients close to diagnosis In thisstudy we wanted to test everyone re-gardless of disease duration so a test-ing method that used both biomarkersworked well If a study was performed ofpurely incident cases which would havean advantage of making the correct di-agnosis early then measuring C-peptidelevels would have little value and furthertesting could be performed on those in-dividuals who had negative results fromtesting for multiple autoantibodies Al-though patients were asked to send aldquopostmealrdquo urine sample the prandialstate of the patient was assumed (andnot observed) therefore we cannot becertain that all UCPCR tests were stimu-lated Our population consisted predomi-nantly (96) of whites and systematicstudies in other especially high-prevalencepopulations are also needed
There aremany strengths of this studyThe result is likely to be representative ofthe clinics studied because 795 of theeligible population took part a result thatshows the high acceptability of this ap-proach in pediatric clinics The systematicbiomarkerndashbased approach that is inde-pendent of clinical features allows atypi-cal patients to be detected (eg thosewith no family history of diabetes) Thisis the first study that has used next-generation sequencing to assess allknown causes of monogenic diabetes al-though themajority of patients (85) hadthe most common types of MODY (GCKHNF1A and HNF4A) so studies that havenot used this approach will have missedonly a few patients
This systematic high-uptake studygives a prevalence of 25 (95 CI 16ndash39) for monogenic diabetes in the UKpediatric population Patients with mono-genic diabetes were identified in everypediatric clinic The successful identifica-tion of patients with monogenic diabe-tes is crucial because they requiredifferent treatment than those withtype 1 or type 2 diabetes The vast major-ity (99) of pediatric patients can be
1886 UK Screening for Pediatric Monogenic Diabetes Diabetes Care Volume 39 November 2016
successfully classified by UCPCR antibodytesting genetic testing and clinical crite-ria UCPCR is a noninvasive and inexpen-sive test which could be more widelyused in the pediatric age group whereit has a high acceptability This screeningalgorithm is a practical approach to de-termining the prevalence of cases in aclinic to ensure the correct diagnosis ofsubtypes of diabetes Confirming a prev-alence of MODY of 25 in the pediatricpopulation indicates that all those in-volved in pediatric diabetes care shouldbe aware of the possibility of an alterna-tive diagnosis and know how to referpatients for genetic testing
Acknowledgments The authors thank the pa-tientswhotookpartinthisstudyandthenurseswhorecruited them for their support with this projectFunding This work presents independent re-search commissioned by the Health InnovationChallenge Fund a parallel funding partnershipbetween theWellcome Trust and the DepartmentofHealth(grantHICF-1009-041)andwassupportedbytheNational Institute forHealthResearch (NIHR)ExeterClinicalResearchFacility and theSouthWestPeninsula Diabetes Research Network MS issupported by the NIHR Exeter Clinical ResearchFacilityTJM is fundedbyanNIHRCSOFellowshipSE and ATH are both Wellcome Trust SeniorInvestigators ERP is a Wellcome Trust New In-vestigator ATH is an NIHR Senior InvestigatorTheviewsexpressed in thispublicationare those
of the authors and not necessarily those of theWellcomeTrust theNHS theNational Institute forHealth Research or the Department of HealthDuality of Interest No potential conflicts ofinterest relevant to this article were reportedAuthor Contributions MS wrote the manu-script and collected and analyzed the data BSanalyzed the data and reviewed and editedthe manuscript SH collected the data andreviewed the manuscript MH coordinatedthe project assistedwith the data and reviewedthe manuscript TJM coordinated the urinaryC-peptide creatinine ratio determination andantibody testing and reviewed the manuscriptKC assistedwith genetic data and reviewed andedited themanuscript RAO contributed to thediscussion and reviewed the manuscript BKdeveloped the protocol submitted the ethicsapplication and reviewed the manuscript CHreviewed the manuscript JC KM CM RSBF SR andSG facilitatedpatient recruitmentwithin their pediatric clinics and reviewed themanuscript SE coordinated the genetic testingand reviewed the manuscript ERP coordi-nated the Tayside arm of the project and re-viewed and edited the manuscript ATHdesigned the study contributed to the discus-sion and reviewed and edited the manuscriptThe UNITED team collected the data MS is theguarantor of this work and as such had fullaccess to all the data in the study and takesresponsibility for the integrity of the data andthe accuracy of the data analysis
References1 Pihoker C Gilliam LK Ellard S et al SEARCHfor Diabetes in Youth Study Group Preva-lence characteristics and clinical diagnosis ofmaturity onset diabetes of the young due to mu-tations inHNF1A HNF4A and glucokinase resultsfrom the SEARCH for Diabetes in Youth J ClinEndocrinol Metab 2013984055ndash40622 Irgens HU Molnes J Johansson BB et al Prev-alence of monogenic diabetes in the population-based Norwegian Childhood Diabetes RegistryDiabetologia 2013561512ndash15193 Carmody D Lindauer KL Naylor RN Adoles-cent non-adherence reveals a genetic cause fordiabetes Diabet Med 201532e20ndashe234 Gandica RG Chung WK Deng L Goland RGallagher MP Identifying monogenic diabetesin a pediatric cohort with presumed type 1 di-abetes Pediatr Diabetes 201516227ndash2335 Lambert AP Ellard S Allen LI et al Identify-ing hepatic nuclear factor 1alpha mutations inchildren and young adults with a clinical diag-nosis of type 1 diabetes Diabetes Care 200326333ndash3376 Thirumalai A Holing E Brown Z Gilliam LK Acase of hepatocyte nuclear factor-1b (TCF2) ma-turity onset diabetes of the youngmisdiagnosedas type 1 diabetes and treated unnecessarilywith insulin J Diabetes 20135462ndash4647 Fendler W Borowiec M Baranowska-Jazwiecka A et al Prevalence of monogenicdiabetes amongst Polish children after a nation-wide genetic screening campaign Diabetologia2012552631ndash26358 Rubio-Cabezas O Edghill EL Argente JHattersley AT Testing for monogenic diabetesamong children and adolescents with antibody-negative clinically defined type 1 diabetes Dia-bet Med 2009261070ndash10749 Murphy R Ellard S Hattersley AT Clinicalimplications of a molecular genetic classifica-tion of monogenic beta-cell diabetes Nat ClinPract Endocrinol Metab 20084200ndash21310 Rubio-Cabezas O Hattersley AT NjoslashlstadPR et al International Society for Pediatricand Adolescent Diabetes ISPAD Clinical PracticeConsensus Guidelines 2014 The diagnosis andmanagement of monogenic diabetes in childrenand adolescents Pediatr Diabetes 201415(Suppl 20)47ndash6411 Craig ME Jefferies C Dabelea D Balde NSeth A Donaghue KC International Societyfor Pediatric and Adolescent Diabetes ISPADClinical Practice Consensus Guidelines 2014Definition epidemiology and classification ofdiabetes in children and adolescents PediatrDiabetes 201415(Suppl 20)4ndash1712 Colclough K Saint-Martin C Timsit J EllardS Bellanne-Chantelot C Clinical utility gene cardfor maturity-onset diabetes of the young Eur JHum Genet 12 February 2014 [Epub ahead ofprint] DOI 101038ejhg20141413 Shields BM Hicks S Shepherd MHColclough K Hattersley AT Ellard S Maturity-onset diabetes of the young (MODY) howmanycases are we missing Diabetologia 2010532504ndash250814 Besser RE Shepherd MH McDonald TJet al Urinary C-peptide creatinine ratio is apractical outpatient tool for identifying hepato-cyte nuclear factor 1-alphahepatocyte nuclearfactor 4-alpha maturity-onset diabetes of the
young from long-duration type 1 diabetes Di-abetes Care 201134286ndash29115 McDonald TJ Knight BA Shields BMBowman P Salzmann MB Hattersley AT Stabil-ity and reproducibility of a single-sample urinaryC-peptidecreatinine ratio and its correlation with24-h urinary C-peptide Clin Chem 2009552035ndash203916 Besser RE Ludvigsson J Jones AG et alUrine C-peptide creatinine ratio is a noninvasivealternative to the mixed-meal tolerance test inchildren and adults with type 1 diabetes Diabe-tes Care 201134607ndash60917 Besser RE Shields BM Hammersley SEet al Home urine C-peptide creatinine ratio(UCPCR) testing can identify type 2 and MODYin pediatric diabetes Pediatr Diabetes 201314181ndash18818 McDonald TJ Colclough K Brown R et alIslet autoantibodies can discriminate maturity-onset diabetes of the young (MODY) from type 1diabetes Diabet Med 2011281028ndash103319 Kanakatti Shankar R Pihoker C Dolan LMet al SEARCH for Diabetes in Youth Study GroupPermanent neonatal diabetes mellitus preva-lence and genetic diagnosis in the SEARCH for Di-abetes in Youth Study Pediatr Diabetes 201314174ndash18020 Hameed S Ellard S Woodhead HJ et alPersistently autoantibody negative (PAN)type 1 diabetes mellitus in children Pediatr Di-abetes 201112142ndash14921 Wheeler BJ Patterson N Love DR et alFrequency and genetic spectrum of maturity-onset diabetes of the young (MODY) in southernNew Zealand J Diabetes Metab Disord 2013124622 Redondo MJ Rodriguez LM Escalante MSmith EO Balasubramanyam A HaymondMW Types of pediatric diabetes mellitus de-fined by anti-islet autoimmunity and randomC-peptide at diagnosis Pediatr Diabetes 201314333ndash34023 Ehtisham S Hattersley AT Dunger DBBarrett TG British Society for Paediatric Endo-crinology and Diabetes Clinical Trials GroupFirst UK survey of paediatric type 2 diabetesand MODY Arch Dis Child 200489526ndash52924 Neu A Feldhahn L Ehehalt S Hub R RankeMB DIARY group Baden-Wurttemberg Type2 diabetes mellitus in children and adolescentsis still a rare disease in Germany a population-based assessment of the prevalence of type 2diabetes and MODY in patients aged 0-20 yearsPediatr Diabetes 200910468ndash47325 Amed S Dean HJ Panagiotopoulos C et alType 2 diabetes medication-induced diabetesand monogenic diabetes in Canadian children aprospective national surveillance study Diabe-tes Care 201033786ndash79126 Galler A Stange T Muller G et al Child-hood Diabetes Registry in Saxony Germany In-cidence of childhood diabetes in children agedless than 15 years and its clinical and metaboliccharacteristics at the time of diagnosis datafrom the Childhood Diabetes Registry of Sax-ony Germany Horm Res Paediatr 201074285ndash29127 Schober E Rami B Grabert M et al DPV-Wiss Initiative of the GermanWorking Group forPaediatric Diabetology and Phenotypical as-pects of maturity-onset diabetes of the young
carediabetesjournalsorg Shepherd and Associates 1887
(MODY diabetes) in comparison with type 2 di-abetes mellitus (T2DM) in children and adoles-cents experience from a large multicentredatabase Diabet Med 200926466ndash47328 Freeman JV Cole TJ Chinn S et al Crosssectional stature and weight reference curvesfor the UK 1990 Arch Dis Child 19957317ndash2429 Ellard S Lango Allen H De Franco E et alImproved genetic testing for monogenic diabe-tes using targeted next-generation sequencingDiabetologia 2013561958ndash196330 Awa WL Thon A Raile K et al DPV-WissStudy Group Genetic and clinical characteristicsof patients with HNF1A gene variations from the
German-Austrian DPV database Eur J Endocri-nol 2011164513ndash52031 Health amp Social Care Information CentreNational diabetes audit 2011-12 report 1 careprocesses and treatment targets CCG and LHGdata tables [Internet] 2013 Available fromhttpwwwhscicgovuksearchcatalogueproductid=13129ampq=22National+diabetes+audit22ampsort=Relevanceampsize=10amppage=1top Ac-cessed 3 January 201632 Diabetes in Scotland Scottish Diabetes Sur-vey 2014 [Internet] 2014 Available from httpwwwdiabetesinscotlandorgukPublicationsSDS2014pdf Accessed 3 January 2016
33 Vaziri-Sani F Delli AJ Elding-Larsson Het al A novel triple mix radiobinding assay forthe three ZnT8 (ZnT8-RWQ) autoantibody vari-ants in children with newly diagnosed diabetesJ Immunol Methods 201137125ndash3734 Yorifuji T Fujimaru R Hosokawa Y et alComprehensive molecular analysis of Japa-nese patients with pediatric-onset MODY-type diabetes mellitus Pediatr Diabetes20121326ndash3235 Chambers C Fouts A Dong F et al Charac-teristics of maturity onset diabetes of the youngin a large diabetes center Pediatr Diabetes201617360ndash367
1888 UK Screening for Pediatric Monogenic Diabetes Diabetes Care Volume 39 November 2016
successfully classified by UCPCR antibodytesting genetic testing and clinical crite-ria UCPCR is a noninvasive and inexpen-sive test which could be more widelyused in the pediatric age group whereit has a high acceptability This screeningalgorithm is a practical approach to de-termining the prevalence of cases in aclinic to ensure the correct diagnosis ofsubtypes of diabetes Confirming a prev-alence of MODY of 25 in the pediatricpopulation indicates that all those in-volved in pediatric diabetes care shouldbe aware of the possibility of an alterna-tive diagnosis and know how to referpatients for genetic testing
Acknowledgments The authors thank the pa-tientswhotookpartinthisstudyandthenurseswhorecruited them for their support with this projectFunding This work presents independent re-search commissioned by the Health InnovationChallenge Fund a parallel funding partnershipbetween theWellcome Trust and the DepartmentofHealth(grantHICF-1009-041)andwassupportedbytheNational Institute forHealthResearch (NIHR)ExeterClinicalResearchFacility and theSouthWestPeninsula Diabetes Research Network MS issupported by the NIHR Exeter Clinical ResearchFacilityTJM is fundedbyanNIHRCSOFellowshipSE and ATH are both Wellcome Trust SeniorInvestigators ERP is a Wellcome Trust New In-vestigator ATH is an NIHR Senior InvestigatorTheviewsexpressed in thispublicationare those
of the authors and not necessarily those of theWellcomeTrust theNHS theNational Institute forHealth Research or the Department of HealthDuality of Interest No potential conflicts ofinterest relevant to this article were reportedAuthor Contributions MS wrote the manu-script and collected and analyzed the data BSanalyzed the data and reviewed and editedthe manuscript SH collected the data andreviewed the manuscript MH coordinatedthe project assistedwith the data and reviewedthe manuscript TJM coordinated the urinaryC-peptide creatinine ratio determination andantibody testing and reviewed the manuscriptKC assistedwith genetic data and reviewed andedited themanuscript RAO contributed to thediscussion and reviewed the manuscript BKdeveloped the protocol submitted the ethicsapplication and reviewed the manuscript CHreviewed the manuscript JC KM CM RSBF SR andSG facilitatedpatient recruitmentwithin their pediatric clinics and reviewed themanuscript SE coordinated the genetic testingand reviewed the manuscript ERP coordi-nated the Tayside arm of the project and re-viewed and edited the manuscript ATHdesigned the study contributed to the discus-sion and reviewed and edited the manuscriptThe UNITED team collected the data MS is theguarantor of this work and as such had fullaccess to all the data in the study and takesresponsibility for the integrity of the data andthe accuracy of the data analysis
References1 Pihoker C Gilliam LK Ellard S et al SEARCHfor Diabetes in Youth Study Group Preva-lence characteristics and clinical diagnosis ofmaturity onset diabetes of the young due to mu-tations inHNF1A HNF4A and glucokinase resultsfrom the SEARCH for Diabetes in Youth J ClinEndocrinol Metab 2013984055ndash40622 Irgens HU Molnes J Johansson BB et al Prev-alence of monogenic diabetes in the population-based Norwegian Childhood Diabetes RegistryDiabetologia 2013561512ndash15193 Carmody D Lindauer KL Naylor RN Adoles-cent non-adherence reveals a genetic cause fordiabetes Diabet Med 201532e20ndashe234 Gandica RG Chung WK Deng L Goland RGallagher MP Identifying monogenic diabetesin a pediatric cohort with presumed type 1 di-abetes Pediatr Diabetes 201516227ndash2335 Lambert AP Ellard S Allen LI et al Identify-ing hepatic nuclear factor 1alpha mutations inchildren and young adults with a clinical diag-nosis of type 1 diabetes Diabetes Care 200326333ndash3376 Thirumalai A Holing E Brown Z Gilliam LK Acase of hepatocyte nuclear factor-1b (TCF2) ma-turity onset diabetes of the youngmisdiagnosedas type 1 diabetes and treated unnecessarilywith insulin J Diabetes 20135462ndash4647 Fendler W Borowiec M Baranowska-Jazwiecka A et al Prevalence of monogenicdiabetes amongst Polish children after a nation-wide genetic screening campaign Diabetologia2012552631ndash26358 Rubio-Cabezas O Edghill EL Argente JHattersley AT Testing for monogenic diabetesamong children and adolescents with antibody-negative clinically defined type 1 diabetes Dia-bet Med 2009261070ndash10749 Murphy R Ellard S Hattersley AT Clinicalimplications of a molecular genetic classifica-tion of monogenic beta-cell diabetes Nat ClinPract Endocrinol Metab 20084200ndash21310 Rubio-Cabezas O Hattersley AT NjoslashlstadPR et al International Society for Pediatricand Adolescent Diabetes ISPAD Clinical PracticeConsensus Guidelines 2014 The diagnosis andmanagement of monogenic diabetes in childrenand adolescents Pediatr Diabetes 201415(Suppl 20)47ndash6411 Craig ME Jefferies C Dabelea D Balde NSeth A Donaghue KC International Societyfor Pediatric and Adolescent Diabetes ISPADClinical Practice Consensus Guidelines 2014Definition epidemiology and classification ofdiabetes in children and adolescents PediatrDiabetes 201415(Suppl 20)4ndash1712 Colclough K Saint-Martin C Timsit J EllardS Bellanne-Chantelot C Clinical utility gene cardfor maturity-onset diabetes of the young Eur JHum Genet 12 February 2014 [Epub ahead ofprint] DOI 101038ejhg20141413 Shields BM Hicks S Shepherd MHColclough K Hattersley AT Ellard S Maturity-onset diabetes of the young (MODY) howmanycases are we missing Diabetologia 2010532504ndash250814 Besser RE Shepherd MH McDonald TJet al Urinary C-peptide creatinine ratio is apractical outpatient tool for identifying hepato-cyte nuclear factor 1-alphahepatocyte nuclearfactor 4-alpha maturity-onset diabetes of the
young from long-duration type 1 diabetes Di-abetes Care 201134286ndash29115 McDonald TJ Knight BA Shields BMBowman P Salzmann MB Hattersley AT Stabil-ity and reproducibility of a single-sample urinaryC-peptidecreatinine ratio and its correlation with24-h urinary C-peptide Clin Chem 2009552035ndash203916 Besser RE Ludvigsson J Jones AG et alUrine C-peptide creatinine ratio is a noninvasivealternative to the mixed-meal tolerance test inchildren and adults with type 1 diabetes Diabe-tes Care 201134607ndash60917 Besser RE Shields BM Hammersley SEet al Home urine C-peptide creatinine ratio(UCPCR) testing can identify type 2 and MODYin pediatric diabetes Pediatr Diabetes 201314181ndash18818 McDonald TJ Colclough K Brown R et alIslet autoantibodies can discriminate maturity-onset diabetes of the young (MODY) from type 1diabetes Diabet Med 2011281028ndash103319 Kanakatti Shankar R Pihoker C Dolan LMet al SEARCH for Diabetes in Youth Study GroupPermanent neonatal diabetes mellitus preva-lence and genetic diagnosis in the SEARCH for Di-abetes in Youth Study Pediatr Diabetes 201314174ndash18020 Hameed S Ellard S Woodhead HJ et alPersistently autoantibody negative (PAN)type 1 diabetes mellitus in children Pediatr Di-abetes 201112142ndash14921 Wheeler BJ Patterson N Love DR et alFrequency and genetic spectrum of maturity-onset diabetes of the young (MODY) in southernNew Zealand J Diabetes Metab Disord 2013124622 Redondo MJ Rodriguez LM Escalante MSmith EO Balasubramanyam A HaymondMW Types of pediatric diabetes mellitus de-fined by anti-islet autoimmunity and randomC-peptide at diagnosis Pediatr Diabetes 201314333ndash34023 Ehtisham S Hattersley AT Dunger DBBarrett TG British Society for Paediatric Endo-crinology and Diabetes Clinical Trials GroupFirst UK survey of paediatric type 2 diabetesand MODY Arch Dis Child 200489526ndash52924 Neu A Feldhahn L Ehehalt S Hub R RankeMB DIARY group Baden-Wurttemberg Type2 diabetes mellitus in children and adolescentsis still a rare disease in Germany a population-based assessment of the prevalence of type 2diabetes and MODY in patients aged 0-20 yearsPediatr Diabetes 200910468ndash47325 Amed S Dean HJ Panagiotopoulos C et alType 2 diabetes medication-induced diabetesand monogenic diabetes in Canadian children aprospective national surveillance study Diabe-tes Care 201033786ndash79126 Galler A Stange T Muller G et al Child-hood Diabetes Registry in Saxony Germany In-cidence of childhood diabetes in children agedless than 15 years and its clinical and metaboliccharacteristics at the time of diagnosis datafrom the Childhood Diabetes Registry of Sax-ony Germany Horm Res Paediatr 201074285ndash29127 Schober E Rami B Grabert M et al DPV-Wiss Initiative of the GermanWorking Group forPaediatric Diabetology and Phenotypical as-pects of maturity-onset diabetes of the young
carediabetesjournalsorg Shepherd and Associates 1887
(MODY diabetes) in comparison with type 2 di-abetes mellitus (T2DM) in children and adoles-cents experience from a large multicentredatabase Diabet Med 200926466ndash47328 Freeman JV Cole TJ Chinn S et al Crosssectional stature and weight reference curvesfor the UK 1990 Arch Dis Child 19957317ndash2429 Ellard S Lango Allen H De Franco E et alImproved genetic testing for monogenic diabe-tes using targeted next-generation sequencingDiabetologia 2013561958ndash196330 Awa WL Thon A Raile K et al DPV-WissStudy Group Genetic and clinical characteristicsof patients with HNF1A gene variations from the
German-Austrian DPV database Eur J Endocri-nol 2011164513ndash52031 Health amp Social Care Information CentreNational diabetes audit 2011-12 report 1 careprocesses and treatment targets CCG and LHGdata tables [Internet] 2013 Available fromhttpwwwhscicgovuksearchcatalogueproductid=13129ampq=22National+diabetes+audit22ampsort=Relevanceampsize=10amppage=1top Ac-cessed 3 January 201632 Diabetes in Scotland Scottish Diabetes Sur-vey 2014 [Internet] 2014 Available from httpwwwdiabetesinscotlandorgukPublicationsSDS2014pdf Accessed 3 January 2016
33 Vaziri-Sani F Delli AJ Elding-Larsson Het al A novel triple mix radiobinding assay forthe three ZnT8 (ZnT8-RWQ) autoantibody vari-ants in children with newly diagnosed diabetesJ Immunol Methods 201137125ndash3734 Yorifuji T Fujimaru R Hosokawa Y et alComprehensive molecular analysis of Japa-nese patients with pediatric-onset MODY-type diabetes mellitus Pediatr Diabetes20121326ndash3235 Chambers C Fouts A Dong F et al Charac-teristics of maturity onset diabetes of the youngin a large diabetes center Pediatr Diabetes201617360ndash367
1888 UK Screening for Pediatric Monogenic Diabetes Diabetes Care Volume 39 November 2016
(MODY diabetes) in comparison with type 2 di-abetes mellitus (T2DM) in children and adoles-cents experience from a large multicentredatabase Diabet Med 200926466ndash47328 Freeman JV Cole TJ Chinn S et al Crosssectional stature and weight reference curvesfor the UK 1990 Arch Dis Child 19957317ndash2429 Ellard S Lango Allen H De Franco E et alImproved genetic testing for monogenic diabe-tes using targeted next-generation sequencingDiabetologia 2013561958ndash196330 Awa WL Thon A Raile K et al DPV-WissStudy Group Genetic and clinical characteristicsof patients with HNF1A gene variations from the
German-Austrian DPV database Eur J Endocri-nol 2011164513ndash52031 Health amp Social Care Information CentreNational diabetes audit 2011-12 report 1 careprocesses and treatment targets CCG and LHGdata tables [Internet] 2013 Available fromhttpwwwhscicgovuksearchcatalogueproductid=13129ampq=22National+diabetes+audit22ampsort=Relevanceampsize=10amppage=1top Ac-cessed 3 January 201632 Diabetes in Scotland Scottish Diabetes Sur-vey 2014 [Internet] 2014 Available from httpwwwdiabetesinscotlandorgukPublicationsSDS2014pdf Accessed 3 January 2016
33 Vaziri-Sani F Delli AJ Elding-Larsson Het al A novel triple mix radiobinding assay forthe three ZnT8 (ZnT8-RWQ) autoantibody vari-ants in children with newly diagnosed diabetesJ Immunol Methods 201137125ndash3734 Yorifuji T Fujimaru R Hosokawa Y et alComprehensive molecular analysis of Japa-nese patients with pediatric-onset MODY-type diabetes mellitus Pediatr Diabetes20121326ndash3235 Chambers C Fouts A Dong F et al Charac-teristics of maturity onset diabetes of the youngin a large diabetes center Pediatr Diabetes201617360ndash367
1888 UK Screening for Pediatric Monogenic Diabetes Diabetes Care Volume 39 November 2016
