Metabolism USMLE Step 1 Practice Question
A 3-year-old boy presents with developmental delay and recurrent upper airway infections. Vital signs show HR 110/min, RR 28/min, BP 105/65 mmHg, temperature 37.2°C. Physical examination reveals coarse facial features, corneal clouding, macroglossia, and hepatosplenomegaly. Laboratory studies demonstrate elevated urinary glycosaminoglycans. No cardiac murmurs are appreciated. Which enzyme deficiency most likely explains this clinical presentation?
Answer choices
- AIduronate 2 sulfatase
- BAcid alpha glucosidase
- CAlpha L iduronidaseCorrect answer
- DHexosaminidase A
- EPhenylalanine hydroxylase
- FGalactocerebrosidase
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