A 3-year-old boy has global developmental delay, coarse facial features, hepatosplenomegaly, corneal clouding, and dysostosis multiplex on radiographs. Enzyme assay shows deficiency of alpha-L-iduronidase. Urine shows elevated dermatan sulfate and heparan sulfate. Which lysosomal storage disorder is this?

• A Hurler syndrome (MPS I) ✓
• B Hunter syndrome (MPS II)
• C Sanfilippo syndrome (MPS III)
• D Morquio syndrome (MPS IV)

Explanation

Hurler syndrome (mucopolysaccharidosis type I, MPS I) is caused by deficiency of alpha-L-iduronidase, leading to accumulation of dermatan sulfate and heparan sulfate. It presents in infancy/early childhood with coarse facies, corneal clouding (distinguishing it from Hunter syndrome), hepatosplenomegaly, dysostosis multiplex, cardiac disease, and severe intellectual disability. Hunter syndrome (MPS II) is X-linked and lacks corneal clouding; Sanfilippo (MPS III) primarily affects the CNS with minimal somatic features; Morquio (MPS IV) shows severe skeletal involvement without intellectual disability.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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