Acrodermatitis enteropathica is caused by zinc deficiency due to a mutation in ZIP4 transporter. What is the ROLE of zinc that explains the dermatitis, alopecia, and immune deficiency seen in this condition?
- A Zinc is a cofactor for thyroid peroxidase; deficiency causes hypothyroidism
- B Zinc is a structural component of zinc-finger transcription factors, metalloenzymes (SOD, carbonic anhydrase, alkaline phosphatase), and is required for T-lymphocyte development ✓
- C Zinc deficiency causes hemolytic anemia similar to selenium deficiency
- D Zinc is exclusively required for collagen cross-linking
Explanation
Zinc is essential for >300 enzymes and >1000 transcription factors containing zinc-finger domains (Cys2His2 motifs stabilized by Zn2+). Critical functions: (1) SOD1 (copper-zinc SOD) — antioxidant defense; (2) carbonic anhydrase — CO2 transport and acid-base balance; (3) alkaline phosphatase — bone mineralization; (4) thymulin (thymic hormone) requires zinc for bioactivity — zinc deficiency impairs T-cell maturation and thymic involution. The skin requires zinc for keratinocyte differentiation (explain dermatitis/alopecia). Hair follicle and immune cell rapid proliferation requires zinc-dependent enzymes for DNA synthesis.
Reference: Harper's Illustrated Biochemistry, 32nd ed.
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Written and medically reviewed by the StethoPrep medical team.