Which Fredrickson Type corresponds to Familial chylomicronemia (LPL deficiency)?

• A. Type I
• B. Type IIa
• C. Type IIb
• D. Type III

Answer: (A)

In this pattern of lipoprotein disorders, the defining feature is which lipoprotein accumulates in the blood. Familial chylomicronemia happens when triglyceride-rich chylomicrons aren’t cleared because lipoprotein lipase can’t work properly, as in LPL deficiency. That produces a plasma dominated by chylomicrons with very high triglycerides, while LDL and HDL-related abnormalities aren’t the primary issue.

This maps to Type I in the Fredrickson system: a strong emphasis on chylomicrons and marked fasting hypertriglyceridemia, with chylomicrons detectable in the plasma and relatively normal cholesterol levels. Other types involve either elevated LDL alone (Type IIa), both LDL and VLDL (Type IIb), or remnant particles from ApoE-related problems (Type III); none describe isolated chylomicronemia from LPL deficiency.