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ZINC & SKIN
A 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 on
fi nger fl exural creases
Chronic zinc defi ciency with scaly eczema on the
perianal area. Note
peripheral collarette scaling
Beau’s line on thumbnail in a case of zinc depletion syndrome,
appearing
one month after start of zinc therapy. Note faster growth of left
thumb nail,
typically seen in right-handed patients.
Transcription and translation
A 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.
Replication
Further 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 Preparations
Zinc 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 zinc
Age 7-36 months: 3 mg elemental zinc
Age 4-8: 5 mg elemental zinc
Age 9-13: 8 mg elemental zinc
Age 14 and older: 11 mg (men) or 8 mg (women) elemental zinc
Pregnancy and Lactation: 11-12 mg elemental zinc