Metabolism USMLE Step 1 Practice Question
A 3-month-old girl presents with poor feeding and weak crying. Vital signs show HR 152, RR 38, BP 78/52, temp 37°C, SpO2 98% on room air. Examination reveals marked hypotonia and hepatomegaly. Chest radiograph demonstrates cardiomegaly with echocardiography confirming hypertrophic cardiomyopathy. Serum creatine kinase is elevated at 285 U/L. Muscle biopsy shows glycogen accumulation within lysosomes. No developmental delay is noted. Which enzyme deficiency is most likely responsible?
Answer choices
- APyruvate carboxylase
- BDebranching enzyme
- CGlucose 6 phosphatase
- DAcid alpha glucosidaseCorrect answer
- ELysosomal acid lipase
- FLysosomal acid phosphatase
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