A 6-month-old infant presents with coarse facial features, corneal clouding, hepatosplenomegaly, and skeletal deformities. Urine spot test for glycosaminoglycans (GAGs) is positive (dermatan and heparan sulphate). Enzyme assay is most likely to show deficiency of:
- A Alpha-L-iduronidase ✓
- B Iduronate-2-sulphatase
- C N-acetylgalactosamine-4-sulphatase
- D Beta-galactosidase
Correct answer: A. Alpha-L-iduronidase
Explanation
Mucopolysaccharidosis type I (Hurler syndrome) presents in infancy with coarse facies, corneal clouding, hepatosplenomegaly, dysostosis multiplex, and accumulation of dermatan and heparan sulphate due to deficiency of alpha-L-iduronidase (IDUA gene, autosomal recessive). Iduronate-2-sulphatase deficiency causes MPS II (Hunter syndrome, X-linked, no corneal clouding). N-acetylgalactosamine-4-sulphatase deficiency causes MPS VI. Beta-galactosidase deficiency causes GM1 gangliosidosis.
Reference: Ghai Essential Pediatrics, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.