Lipid Biochemistry USMLE Step 1 Practice Question
A 36-year-old man presents with recurrent acute pancreatitis, eruptive xanthomas, and lipemia retinalis. Vital signs show BP 138/88, HR 92, RR 18, temp 37°C, SpO₂ 98% on room air. Serum triglycerides are 8,500 mg/dL with normal LDL cholesterol. Genetic testing excludes lipoprotein lipase and apoC-II mutations. Hepatic lipase activity is severely reduced. He denies alcohol use. Which lipoprotein abnormality characterizes this condition?
Answer choices
- AChylomicron remnant accumulation with normal VLDL
- BProfound HDL deficiency with apoA-I accumulation
- CIsolated LDL elevation with normal triglycerides
- DSevere chylomicronemia with cholesterol-rich particles
- EAccumulation of VLDL remnants (IDL) due to impaired triglyceride hydrolysisCorrect answer
- FType III hyperlipoproteinemia (ApoE2/E2 homozygosity)
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