A 14-year-old boy has clustered dark-red papules over the scrotum and lower back, episodes of burning pain in the extremities triggered by heat, and corneal verticillata. His maternal uncle died young of renal failure. Deficiency of which enzyme explains these findings?

• A Iduronate sulfatase
• B Acid sphingomyelinase
• C Glucocerebrosidase
• D Alpha-galactosidase A ✓

Explanation

Fabry disease, an X-linked lysosomal storage disorder due to alpha-galactosidase D deficiency, accumulates ceramide trihexoside (globotriaosylceramide). It causes angiokeratoma corporis diffusum, acroparaesthesiae, corneal verticillata, cardiomyopathy, strokes, and progressive renal failure. Acid sphingomyelinase deficiency causes Niemann-Pick disease, glucocerebrosidase deficiency causes Gaucher disease, and iduronate sulfatase deficiency causes Hunter syndrome.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.