A 3-month-old infant presents with coarse facial features, gingival hypertrophy, macroglossia, hepatosplenomegaly, and corneal clouding. Urine spot test for glycosaminoglycans is positive. Enzyme assay shows deficiency of alpha-L-iduronidase. Which mucopolysaccharide accumulates, and what is the MODE OF INHERITANCE?

• A Heparan sulfate alone; X-linked recessive inheritance
• B Keratan and chondroitin sulfate; autosomal dominant inheritance
• C Heparan and dermatan sulfate; autosomal recessive inheritance ✓
• D Dermatan sulfate alone; autosomal recessive inheritance

Explanation

Alpha-L-iduronidase deficiency causes Mucopolysaccharidosis type I (MPS I), which includes Hurler syndrome (severe), Hurler-Scheie, and Scheie syndromes. This enzyme is required for degradation of both heparan sulfate and dermatan sulfate. Both substrates accumulate. MPS I is autosomal recessive. Corneal clouding is a characteristic feature distinguishing it from Hunter syndrome (MPS II, X-linked recessive, no corneal clouding). Keratan sulfate accumulates in MPS IV (Morquio). No MPS follows autosomal dominant inheritance.

Reference: Ghai Essential Pediatrics, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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