Lipid Biochemistry USMLE Step 1 Practice Question
A 62-year-old man with a history of myocardial infarction is found to have extremely low LDL cholesterol (25 mg/dL) and very low plasma levels of apolipoprotein B-containing lipoproteins. He reports a lifelong history of fat malabsorption and steatorrhea. Genetic testing reveals mutations affecting microsomal triglyceride transfer protein (MTP). Which of the following best describes the pathophysiology?
Answer choices
- AImpaired assembly and secretion of apoB-containing lipoproteins from liver and intestineCorrect answer
- BImpaired synthesis of apolipoprotein B-100 mRNA
- CLoss-of-function mutation in lipoprotein lipase gene
- DAccelerated catabolism of LDL particles by enhanced hepatic receptor activity
- EIncreased clearance of VLDL by peripheral lipoprotein lipase
- FHomozygous PCSK9 loss-of-function mutation
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