Metabolism USMLE Step 1 Practice Question
A 10-month-old boy presents with progressive developmental regression and an exaggerated startle response over the past 2 months. Vital signs: HR 118/min, RR 28/min, Temp 37.2Ā°C. Funduscopic examination reveals a cherry red macula. Serum acid phosphatase is elevated at 18 U/L (normal: 2-10). Hepatosplenomegaly is absent. The child takes no medications. Which enzyme deficiency most likely explains these findings?
Answer choices
- AAlpha galactosidase A
- BSphingomyelinase
- CArylsulfatase A
- DBeta glucocerebrosidase
- EHexosaminidase ACorrect answer
- FGalactocerebrosidase
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