1. Copy number variations in monozygotic twins discordant for schizophrenia Christina A. Castellani, Sujit Maiti, Kiran Kumar HB, Richard L. OReilly and Shiva M. Singh The University of Western Ontario

2. Schizophrenia, OMIM 181500 > 1% of the population Characterized by a distortion of reality Heritability estimates of ~80% Significant disease heterogeneity Most cases singleton in the family Complex inheritance patterns Greatest risk is family history 3. Complex and Subjective diagnosis 4. Schizophrenia Inheritance 5. Search for genes: progress to date Chromosomal abnormalities (22q11, 1q42.1) Candidate gene approach (COMT, PRODH) Early linkage based on few markers (DTNBP1, NRG1, DAOA) Genome wide association studies (ZNF804A) Despite increasing numbers (>6,000) of patients and controls (>12,000), few genes have been identified and results are difficult to reproduce Conclusions? 6. Two Unique Families Family - 1 I-2-1 Schizophrenia I-2-2 Bipolar Disorder I-1-1 Compulsive Personality Disorder I-1-2 Family - 2 II-2-1 Schizophrenia II-2-2 II-1-1 II-1-2 7. Copy Number Variation A candidate for disease associated variation in humans Variable copies of DNA segments DNA deletions, insertions, duplications > 1kb and up to several mb 77% of CNVs are currently predicted to include genes Covering about 12% of the genome in healthy individuals 8. Affymetrix Genome Wide Human SNP Array 6.0 Median intermarker distance of less than 700 bp Provides breakpoint identification 1.8 Million Genetic Markers > 906, 000 SNP Probes > 946, 000 CNV Probes Detection of Copy Number Variations 9. Chromosome CNV Architecture Lee, Charles. 2007. Nature Genetics S39. 10. Copy Number Variation (CNV) 11. Distribution of CNV among family members according to size CNVs Size Family 1 Family 2 I-1-1 I-1-2 I-2-1 I-2-2 Total II-1-1 II-1-2 II-2-1 II-2-2 Total 100 to 200 kb 17 18 15 20 70 119 50 24 24 217 >200 to 300 kb 11 6 4 10 31 25 6 13 9 53 >300 to 400 kb 5 5 6 5 21 11 3 1 4 19 >400 to 500 kb 2 0 2 2 6 6 1 1 2 10 >500 to 1000 kb 6 2 4 7 19 7 2 5 2 16 >1 to 10 Mb 9 4 5 3 21 5 2 4 5 16 >10 to 20 Mb 5 0 0 0 5 0 0 0 0 0 >20 Mb 3 0 0 0 3 2 0 2 2 6 Total 58 35 36 47 176 177 64 50 49 340 12. Distribution of CNVs within family members 13. Chromosome Wide CNV Distribution Chr No. Family 1 Family 2 I.1 I.2 II.1 II.2 Total I.1 I.2 II.1 II.2 Total 1 4 2 2 2 10 11 2 6 6 25 2 4 2 5 5 16 11 2 2 3 18 3 1 4 2 3 10 7 4 4 2 17 4 4 3 2 4 13 8 1 3 2 14 5 0 0 0 0 0 12 0 2 1 15 6 0 0 0 0 0 10 2 0 0 12 7 2 6 3 4 15 10 5 3 4 22 8 1 0 3 3 7 7 3 3 3 16 9 1 1 2 3 7 4 4 3 4 15 10 2 1 1 1 5 3 5 1 1 10 11 3 1 2 1 7 5 1 2 2 10 12 0 1 0 1 2 4 3 0 1 8 13 0 0 0 0 0 40 1 1 0 42 14 4 6 3 5 18 4 6 5 3 18 15 4 3 1 3 11 2 6 6 8 22 16 2 1 2 3 8 9 1 1 1 12 17 4 1 2 3 10 8 2 2 1 13 18 0 0 0 0 0 1 0 0 1 2 19 0 1 0 0 1 7 3 2 1 13 20 0 0 0 0 0 0 0 0 1 1 21 1 2 2 3 8 2 3 2 1 8 22 3 0 3 2 8 3 1 1 1 6 X 18 0 1 1 20 9 9 1 2 21 Total 58 35 36 47 176 177 64 50 49 340 14. Gain/Loss Profiles 15. Gain/Loss Profiles 16. Gene and Pathway Analysis Family 1: affected patient (schizophrenia) had unique CNVs that overlapped 8 genes Family 2: affected patient (schizophrenia) had unique CNVs that overlapped 3 genes Genes in the affected individual of family 1 harboured genes involved in starch and sucrose metabolism networks (2.2 E-06) 17. Repeat Elements at de novo CNV Breakpoints 18. de novo CNVs Meiotic de novo (in both twins, N=12) Mitotic de novo (in one twin only, N=28) Three de novo regions that were novel, harbouring three genes PSMC1: 26S protease regulatory subunit 4 C14orf102: highly conserved gene, no known function KIAA0146: function unknown, expressed in brain among other tissues 19. Twin Based Approach 6 pairs of MZ twins discordant for schizophrenia Average number of CNVs per individual = 37.25 Gains more frequent than losses 31 novel CNVs across 12 samples The majority (211 CNVs) were within 100 and 200 kb in size 20. Ingenuity Pathway Analysis (IPA) Physiological System or Disease P-Value # Genes Genetic Disorder 2.16 E-03 - 4.64 E-02 10 Neurological Disease 2.16 E-03 - 4.64 E-02 14 Nervous System Development and Function 9.16 E-03 3 21. In Summary Copy Number Variants were found to: be frequent, harbour repeats at their breakpoints, overlap genes associated with neurological networks, be both meiotic and mitotic in origin vary in location across patients CNV differences can be detected in MZ twins and are patient specific 22. Acknowledgements We would like to acknowledge the following groups for their funding and support: - Canadian Institutes for Health Research (CIHR) - Ontario Mental Health Foundation (OMHF) - Schizophrenia Society of Ontario (SSO) - The University of Western Ontario A special thanks to David Carter (London Regional Genomics Center) and the individuals who contributed samples for use in this study.