A 2-year-old boy presents with coarse facial features, corneal clouding, hepatosplenomegaly, recurrent respiratory infections, and developmental delay. Urinary mucopolysaccharide screen is positive. Which of the following distinguishes Hurler syndrome (MPS I) from Hunter syndrome (MPS II) clinically?

• A Hunter syndrome has corneal clouding; Hurler does not
• B Hunter syndrome is autosomal recessive; Hurler is X-linked
• C Hurler syndrome has corneal clouding; Hunter does not ✓
• D Both have identical clinical features; only enzyme assay distinguishes them

Explanation

Both Hurler (MPS I, alpha-L-iduronidase deficiency, autosomal recessive) and Hunter (MPS II, iduronate sulfatase deficiency, X-linked recessive) syndromes cause coarse facies, hepatosplenomegaly, skeletal dysostosis, and intellectual disability. The key clinical distinction is that Hurler syndrome characteristically has corneal clouding, whereas Hunter syndrome does not have corneal clouding. Hunter syndrome also tends to have a milder and more slowly progressive course. Urinary dermatan sulfate and heparan sulfate are elevated in both.

Reference: Ghai Essential Pediatrics, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.