Metabolism USMLE Step 1 Practice Question
A 13-year-old boy presents with progressive fatigue, easy bruising, and recurrent bone pain over 6 months. Vital signs show BP 105/68, HR 92, RR 18, temp 37.2°C, SpO2 98%. Examination reveals massive splenomegaly; liver is not enlarged. Laboratory studies demonstrate hemoglobin 9.2 g/dL and platelets 65,000/μL. Bone marrow biopsy shows characteristic lipid-laden macrophages with wrinkled tissue paper appearance. Which enzyme deficiency best explains these findings?
Answer choices
- AAlpha galactosidase A
- BBeta glucocerebrosidaseCorrect answer
- CSphingomyelinase
- DLysyl hydroxylase
- EHexosaminidase A
- FArylsulfatase A (metachromatic leukodystrophy)
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