Fredrickson Classification of Inherited Lipoprotein Disorders
The Fredrickson (Fredrickson–Levy–Lees) classification categorizes primary hyperlipoproteinemias into 5 phenotypes (types I–V) based on the lipoprotein pattern present in plasma. [1]
The phenotypes are defined by elevations in specific lipoprotein fractions (chylomicrons, LDL, VLDL, and/or chylomicron remnants/IDL) detectable by lipoprotein fractionation. [1]
Phenotype Definitions (Types I–V)
- Type I (hyperchylomicronemia)
- Elevated lipoprotein fraction: chylomicrons [1]
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Clinical label: familial chylomicronemia syndrome/familial hyperchylomicronemia (historical naming) [2]
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Type IIa (familial hypercholesterolemia pattern)
- Elevated lipoprotein fraction: LDL [1]
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Clinical label: familial hypercholesterolemia (FH) [2]
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Type IIb (combined hyperlipidemia pattern)
- Elevated lipoprotein fractions: LDL and VLDL [1]
-
Clinical label: combined hyperlipidemia [2]
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Type III (dysbetalipoproteinemia pattern)
- Elevated lipoprotein fractions: VLDL and chylomicron remnants (remnant particles) [1]
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Clinical label: dysbetalipoproteinemia [2]
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Type IV (hypertriglyceridemia pattern)
- Elevated lipoprotein fraction: VLDL [1]
-
Clinical label: simple hypertriglyceridemia/familial hypertriglyceridemia (historical naming) [2]
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Type V (mixed hypertriglyceridemia pattern)
- Elevated lipoprotein fractions: chylomicrons and VLDL [1]
- Clinical label: mixed hyperlipidemia/severe hypertriglyceridemia phenotype (historical naming) [2]