A boy has recurrent skin fragility, oral erosions, and milia since birth. Electron microscopy of the skin shows cleavage within the basal keratinocytes (cytolysis of basal cells). The defective protein and inheritance are:

• A Laminin-332; autosomal recessive
• B Collagen VII; autosomal recessive
• C Integrin α6β4; autosomal recessive
• D Keratin 5 or Keratin 14; autosomal dominant (most common) ✓

Explanation

Epidermolysis bullosa simplex (EBS) shows cleavage within basal keratinocytes on electron microscopy due to mutations in KRT5 (keratin 5) or KRT14 (keratin 14), which form the intermediate filament cytoskeleton of basal cells. Most EBS subtypes are autosomal dominant. Junctional EB (JEB) involves laminin-332 or BPAG2 (collagen XVII) with cleavage in the lamina lucida; dystrophic EB (DEB) involves collagen VII with sub-lamina densa cleavage; Kindler syndrome involves FERMT1.

Reference: Neena Khanna Illustrated Synopsis of Dermatology & STD, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.