Metabolism USMLE Step 1 Practice Question
A 7-month-old infant presents with extreme irritability, developmental regression, and feeding difficulty over the past 6 weeks. Vital signs show HR 128/min, RR 26/min, temp 37.2°C. Physical examination reveals hypertonia, optic atrophy, and no hepatosplenomegaly. Nerve conduction studies demonstrate demyelination. Brain MRI shows white matter abnormalities. Cerebrospinal fluid protein is elevated at 89 mg/dL. Sural nerve biopsy reveals pathognomonic multinucleated globoid cells. Which enzyme deficiency best explains these findings?
Answer choices
- AGalactocerebrosidaseCorrect answer
- BArylsulfatase A
- CBeta glucocerebrosidase
- DHexosaminidase A
- EAcid alpha glucosidase
- FSphingomyelinase
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