Lipid Biochemistry USMLE Step 1 Practice Question
A 38-year-old woman with recurrent acute pancreatitis presents with milky serum and severe hypertriglyceridemia (1,800 mg/dL). Vital signs: BP 128/82 mmHg, HR 92/min, RR 18/min, temp 37.2°C, SpO2 98%. Lipoprotein electrophoresis reveals a prominent chylomicron band. Fasting glucose is normal. She denies alcohol use. Symptoms resolve with strict low-fat diet restriction. Which enzyme deficiency best explains her lipid profile abnormality?
Answer choices
- APhospholipase A2
- BHepatic lipase
- CHMG-CoA reductase
- DLipoprotein lipaseCorrect answer
- ELCAT (lecithin-cholesterol acyltransferase)
- FApolipoprotein C-II
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