Metabolism USMLE Step 1 Practice Question
A 2-year-old male presents with progressive neurological deterioration, developmental regression, and cherry-red macular spots on ophthalmologic examination. Vital signs show HR 98/min, RR 22/min, BP 95/62 mmHg, and temperature 37.2°C. Serum hexosaminidase A levels are markedly decreased at 2 U/L (normal: 8-15 U/L), while hexosaminidase B remains normal. The patient denies recent fever. This biochemical defect would most appropriately be categorized as belonging to which of the following general classes of metabolic disorders?
Answer choices
- AMucopolysaccharidosis
- BLipid metabolism
- CGangliosidosisCorrect answer
- DAminoacidopathy
- EPorphyria
- FGlycogen storage disease
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