ZINC & SKINA brief summary

Acrodermatitis Enteropathica (AE)

*Inherited as----- Autosamal recessive trait.*By--------- Danbolt & Closs in 1943

*Defect in---- SLC39A4----encode hZIP4 protein*5D------- (dermatological changes, diarrhea,

developmental impairment, depression & death)*Rx---------- by Zn 3mg/kg/day life long

*220mg tab. Of Zn sulfate = 50mg og elemental Zn

Figure 1. Perioral erosive dermatitis in “acute” zinc deficiency. The severity of erosion, crusting,

and erythema may vary.

Figure 2. Erosive dermatitis affecting the diaper area

Figure 3. Erosion and scald-like erythema on the acral parts

Figure 4. Crusted erythematous plaques in “chronic” zinc deficiency in a case of nephrotic syndrome

Figure 5. Annular (A) and psoriasiform (B) lesions in the same patient

Figure 6. Close up view of the lesions

Figure 7. Follow up picture of a patient of “chronic” zinc deficiency receiving zinc supplementation for 1 month

Figure 8. Histopathology showing parakeratosis, necrosis of upper layers of epidermis and scattered

dyskeratotic cells

Figure 9. Follow up picture of a case with “acute” zinc deficiency after receiving zinc supplementation for 2 weeks. Lesions have healed with transient hyperpigmentation and

hypopigmentation.

Figure 10. Another photograph of the same patient

Hypozincemia :

Type I is characterized by an inherent defect in the absorption of zinc from the gut, i.e., classical AE.

Type II occurs because of impaired secretion of zinc in breast milk.

Type III develops in preterm infants who are put on prolonged parenteral

alimentation deficient in zinc .

(a )Zinc defi ciency in a premature breastfed infant

normal breastfed infant

Acute zinc depletion syndrome with denuded fi nger tips and bullae onfi nger fl exural creases

Chronic zinc defi ciency with scaly eczema on the perianal area. Noteperipheral collarette scaling

Beau’s line on thumbnail in a case of zinc depletion syndrome, appearingone month after start of zinc therapy. Note faster growth of left thumb nail,typically seen in right-handed patients.

Transcription and translationA gene is a sequence of DNA that contains genetic information and can influence the phenotype of an organism. Within a gene, the sequence of bases along a DNA strand defines a messenger RNA sequence, which then defines one or more protein sequences. The relationship between the nucleotide sequences of genes and the amino-acid sequences of proteins is determined by the rules oftranslation, known collectively as the genetic code. The genetic code consists of three-letter 'words' called codons formed from a sequence of three nucleotides (e.g. ACT, CAG, TTT).

In transcription, the codons of a gene are copied into messenger RNA by RNA polymerase. This RNA copy is then decoded by aribosome that reads the RNA sequence by base-pairing the messenger RNA to transfer RNA, which carries amino acids. Since there are 4 bases in 3-letter combinations, there are 64 possible codons ( combinations). These encode the twenty standard amino acids, giving most amino acids more than one possible codon. There are also three 'stop' or 'nonsense' codons signifying the end of the coding region; these are the TAA, TGA and TAG codons.

ReplicationFurther information : DNA replication

Cell division is essential for an organism to grow, but, when a cell divides, it must replicate the DNA in its genome so that the two daughter cells have the same genetic information as their parent. The double-stranded structure of DNA provides a simple mechanism for DNA replication. Here, the two strands are separated and then each strand's complementary DNA sequence is recreated by an enzyme called DNA polymerase. This enzyme makes the complementary strand by finding the correct base through complementary base pairing, and bonding it onto the original strand. As DNA polymerases can only extend a DNA strand in a 5 to 3 direction, different mechanisms are used to ′ ′copy the antiparallel strands of the double helix.[87] In this way, the base on the old strand dictates which base appears on the new strand, and the cell ends up with a perfect copy of its DNA.

Zinc PreparationsZinc Acetate: 25 mg (7.5 mg elemental zinc), 50 mg (15 mg elemental zinc)Zinc Gluconate: 50 mg (7 mg elemental zinc), 100 mg (14 mg elemental zinc)Zinc Sulfate: 110 mg (25 mg elemental zinc), 220 mg (50 mg elemental zinc)Zinc Oxide: 100 mg (80 mg elemental zinc)Dosing: Recommended Daily Allowance (RDA)Age 0-6 months: 2 mg elemental zincAge 7-36 months: 3 mg elemental zincAge 4-8: 5 mg elemental zincAge 9-13: 8 mg elemental zincAge 14 and older: 11 mg (men) or 8 mg (women) elemental zincPregnancy and Lactation: 11-12 mg elemental zinc