A 3-year-old girl presents with alopecia, perioral dermatitis, acrodermatitis enteropathica-like skin lesions, diarrhoea, and failure to thrive. She is exclusively breastfed with minimal complementary feeding. Serum alkaline phosphatase is markedly low. The most likely diagnosis and its inheritance is:

• A Biotin-responsive multiple carboxylase deficiency; autosomal recessive
• B Acrodermatitis enteropathica; autosomal recessive, SLC39A4 mutation ✓
• C Dietary zinc deficiency due to inadequate complementary feeding
• D Cystic fibrosis with fat-soluble vitamin malabsorption

Explanation

Acrodermatitis enteropathica is a rare autosomal recessive disorder caused by mutations in SLC39A4 encoding ZIP4 zinc transporter expressed in the duodenum/jejunum. It typically presents at weaning from breast milk (which contains a unique zinc-binding ligand, picolinic acid) with the triad of acral/periorificial dermatitis, alopecia, and diarrhoea. Markedly low alkaline phosphatase (a zinc-dependent enzyme) is a useful diagnostic clue. Treatment is oral zinc supplementation.

Reference: Ghai Essential Pediatrics, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.