Lipid Biochemistry USMLE Step 1 Practice Question
A 45-year-old man with type 2 diabetes presents with eruptive xanthomas on his elbows and palms. Vital signs: BP 148/92 mmHg, HR 88 bpm, RR 16, Temp 37°C, SpO2 98% RA. Labs show triglycerides 800 mg/dL, total cholesterol 520 mg/dL, LDL 180 mg/dL despite atorvastatin 40 mg daily, and normal apoB-100 synthesis. Liver enzymes and renal function are normal. Which lipoprotein metabolism defect best explains his phenotype?
Answer choices
- AImpaired hepatic triglyceride lipase activityCorrect answer
- BDecreased LDL receptor expression
- CFamilial chylomicronemia syndrome
- DAbsent apolipoprotein C-II
- EHepatic lipase deficiency
- FImpaired lipoprotein lipase activity
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