Lipid Biochemistry USMLE Step 1 Practice Question
A 3-year-old girl from consanguineous parents presents to the emergency department with severe abdominal pain and recurrent pancreatitis. Vital signs show HR 120/min, BP 95/60, RR 24/min, temperature 38.2°C. Laboratory studies reveal lipemic serum, serum triglycerides 1500 mg/dL, and amylase 450 U/L. Serum lipoprotein lipase activity is markedly reduced. Apolipoprotein C-II levels are normal. Which of the following best explains the primary defect in triglyceride metabolism in this patient?
Answer choices
- AImpaired hepatic uptake of remnant particles
- BDefective apolipoprotein C-II production
- CImpaired hepatic synthesis of VLDL
- DImpaired hydrolysis of triglycerides in chylomicrons and VLDLCorrect answer
- EDeficiency of cholesterol ester transfer protein
- FImpaired degradation of apolipoprotein B-100 by hepatic lipase
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