Dermatology · Genodermatoses and Rare Disorders

A 6-month-old formula-fed infant has well-demarcated erythematous scaly plaques around the mouth, anus, and genitals, along with diffuse alopecia, chronic diarrhoea, and recurrent infections. Serum alkaline phosphatase is low. The underlying defect involves impaired absorption of:

  • A Biotin
  • B Zinc
  • C Essential fatty acids
  • D Vitamin B12
Correct answer: B. Zinc

Explanation

Acrodermatitis enteropathica is an autosomal recessive disorder of zinc uptake due to SLC39A4 mutation, producing periorificial and acral dermatitis, alopecia, diarrhoea, and immune impairment; low alkaline phosphatase reflects zinc-dependent enzyme deficiency. Biotin deficiency (biotinidase) causes similar dermatitis but with seizures and lactic acidosis rather than low alkaline phosphatase.

Reference: Nelson Textbook of Pediatrics, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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