A 2-year-old girl is evaluated for short stature, coarse facial features, corneal clouding, joint stiffness, and recurrent upper respiratory infections. Skeletal survey shows J-shaped sella turcica, beaking of vertebral bodies (thoracolumbar gibbus), and widened ribs ('oar-shaped'). Urine MPS analysis shows elevated heparan sulfate and dermatan sulfate. Iduronate-2-sulfatase activity is normal. What is the MOST likely diagnosis?
- A Hunter syndrome (MPS II)
- B Morquio syndrome (MPS IV)
- C Hurler syndrome (MPS IH) ✓
- D Maroteaux-Lamy syndrome (MPS VI)
Explanation
Hurler syndrome (MPS IH) is caused by deficiency of alpha-L-iduronidase, causing accumulation of dermatan sulfate and heparan sulfate. It presents with coarse facies, corneal clouding (unlike Hunter syndrome which has NO corneal clouding), joint stiffness, hepatosplenomegaly, gibbus deformity, and progressive intellectual deterioration. 'Dysostosis multiplex' on skeletal survey includes J-shaped sella, beaking vertebral bodies, and oar-shaped ribs. Normal iduronate-2-sulfatase rules out Hunter syndrome (MPS II). Morquio syndrome (MPS IV) causes keratan sulfate accumulation with normal intelligence and odontoid hypoplasia. Hurler is autosomal recessive; Hunter is X-linked recessive.
Reference: Ghai Essential Pediatrics, 10th ed.
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Written and medically reviewed by the StethoPrep medical team.