A 2-year-old child presents with hepatosplenomegaly, corneal clouding, and coarse facial features. Urine shows elevated heparan sulfate and dermatan sulfate. Which enzyme deficiency is responsible?

• A Glucocerebrosidase — Gaucher disease, no corneal clouding
• B Iduronate-2-sulfatase — Hunter syndrome (MPS II), X-linked, no corneal clouding
• C Alpha-L-iduronidase (IDUA) — Hurler syndrome (MPS I), severe form with corneal clouding ✓
• D Arylsulfatase A — Metachromatic leukodystrophy, primarily neurological with sulfatiduria

Explanation

Hurler syndrome (MPS type I, severe) is caused by deficiency of alpha-L-iduronidase, leading to accumulation of heparan sulfate and dermatan sulfate in lysosomes. Clinical features include hepatosplenomegaly, coarse facies, corneal clouding, skeletal dysostosis multiplex, and mental retardation. Corneal clouding distinguishes Hurler from Hunter syndrome (MPS II, iduronate-2-sulfatase deficiency), which is X-linked and lacks corneal clouding. Gaucher disease involves glucocerebrosidase and cerebroside accumulation, not mucopolysaccharides.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.