A child presents with recurrent blistering after minor trauma since birth. There is no family history. Electron microscopy shows blistering within the lamina lucida. The molecular defect is most likely in:

• A Keratin 5 or 14
• B Type VII collagen
• C Plectin
• D Laminin 332 (laminin-5) ✓

Explanation

Epidermolysis bullosa (EB) junctionalis involves blistering in the lamina lucida. The most common cause is mutation in LAMA3, LAMB3, or LAMC2 genes encoding laminin-332 (laminin-5). Keratin 5/14 mutations cause EB simplex (intraepidermal, within basal keratinocytes). Type VII collagen mutations cause dystrophic EB (sub-lamina densa). Plectin mutations cause EB simplex with muscular dystrophy. EB junctionalis Herlitz subtype (LAMB3) is lethal.

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.