A newborn develops flaccid bullae at sites of friction and handling from the first day of life. Blisters heal within days leaving no scars, and nails and teeth are normal. Family history reveals a parent with similar blistering in childhood. The defect lies in which proteins?

• A Type VII collagen
• B Laminin 332
• C Type XVII collagen
• D Keratins 5 and 14 ✓

Explanation

Epidermolysis bullosa simplex is the commonest form, inherited usually as autosomal dominant, with intraepidermal basal layer cleavage due to mutations in keratin 5 and keratin 14. Blistering occurs at pressure and friction points, heals without scarring, and improves with age. Type VII collagen defects cause dystrophic EB with scarring and milia, laminin 332 defects cause lethal junctional EB, and type XVII collagen defects cause junctional EB generalized intermediate.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.