An 8-year-old boy has coarse facial features, macrocephaly, stiff joints, hepatosplenomegaly and hearing loss, but his corneas are clear on slit-lamp examination and intellect is only mildly affected. Urinary glycosaminoglycans show increased dermatan sulfate and heparan sulfate. Which statement about his condition is correct?

• A It is inherited as an autosomal recessive trait and iduronidase is deficient
• B It is autosomal recessive and N-acetylglucosamine-6-sulfatase is deficient
• C It is X-linked recessive and iduronate sulfatase is deficient ✓
• D It is X-linked recessive and sulfamidase is deficient

Explanation

Hunter syndrome (MPS II) is the only X-linked mucopolysaccharidosis, caused by iduronate sulfatase deficiency. Unlike Hurler syndrome (MPS I), corneal clouding is characteristically absent and cognitive decline is slower, making clear corneas the discriminating sign. Option A describes Hurler syndrome, option B describes Sanfilippo syndrome (MPS III), and option D describes Sanfilippo A, all autosomal recessive.

Reference: Nelson Textbook of Pediatrics, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.