Chylomicrons are present in which dyslipidemia?

• A. Familial hypercholesterolemia
• B. Hypertriglyceridemia
• C. Deficiency in lipoprotein lipase activity
• D. Familial hypoalphalipoproteinemia

Answer: (C)

Chylomicrons are normally cleared from the blood after a meal by lipoprotein lipase (LPL) acting on the triglycerides in these particles, with ApoC-II as a necessary cofactor. When LPL activity is deficient, the hydrolysis of triglycerides in chylomicrons can’t occur, so these particles persist in circulation, leading to severe hypertriglyceridemia and a chylomicronemia syndrome. This makes lipoprotein lipase deficiency the dyslipidemia that features chylomicrons in the blood. The other conditions involve different lipoprotein abnormalities (for example, high LDL in familial hypercholesterolemia and low HDL in familial hypoalphalipoproteinemia), and hypertriglyceridemia can arise from other mechanisms that don’t necessarily involve persistent chylomicrons.