A 35-year-old man presents with progressive visual loss and yellowish papules in the flexures of his neck and axillae. Fundoscopy shows irregular radial streaks extending from the optic disc. The most likely genetic mutation is in which gene?

• A ABCC6 ✓
• B COL7A1
• C FBN1
• D COL3A1

Explanation

Pseudoxanthoma elasticum (PXE) is an autosomal recessive disorder caused by mutations in the ABCC6 gene, which encodes a transmembrane transporter. This leads to mineralization and fragmentation of elastic fibers in the skin, eyes, and vasculature. The classic triad includes yellowish papules in flexures, angioid streaks on fundoscopy, and cardiovascular complications. COL7A1 is associated with dystrophic epidermolysis bullosa, FBN1 with Marfan syndrome, and COL3A1 with vascular Ehlers-Danlos syndrome.

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.