Lipoprotein disorders classification

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief:

Lipoprotein Disorders Microchapters
Patient Information
Overview
Causes
Classification Hyperlipoproteinemia Hypolipoproteinemia
Treatment

Overview

Lipoprotein disorders can be classified according to the Fredrickson classification which is based on the pattern of lipoproteins on electrophoresis or ultracentrifugation. It was later adopted by the World Health Organization (WHO). It does not directly account for HDL, and it does not distinguish among the different genes that may be partially responsible for some of these conditions. It remains a popular system of classification, but is considered outdated by many.

Classification

There are several ways in which lipoprotein abnormalities are classified. Lipoprotein disorders can be classified according to:

• The pattern of change in the lipoprotein levels, described as hyperlipidemia (increase in lipid levels) and hypolipidemia (decrease in lipid levels): However, this classification is problematic because the lipids and lipoproteins levels in some situation can be elevated in some types of lipoproteins and lipids and decreased in others.

• Phenotype, or the specific type of lipid that is increased, as classified by Fredrickson: This classification is problematic because it does not include abnormalities in the level of HDL.

• Etiology, as primary (genetic) or secondary to another condition: This classification can be problematic, because most conditions involve the intersection of genetics and lifestyle issues. However, there are a few well defined genetic conditions that are usually easy to identify.

• Levels of measured lipids (cholesterol and triglycerides), described as hypercholesterolemia and hypocholesterolemia or hypertriglyceridimia and hypotriglyceridemia: This distinction is not specific because it does not reflect the specific lipoprotein(s) that are abnormally high or low.

Fredrickson Classification of Hyperlipoproteinemia

Hyperlipoproteinemia/Hyperlipidemia

Type I: Familial hyperchylomicronemia

Type II

Type III: Dysbetalipoproteinemia

Type IV: Primary hypertriglyceridemia

Type V: Mixed hyperlipoproteinemia

Type A: Familial hypercholesterolemia

Type B: Familial combined hyperlipidemia

Fredrickson classification of Hyperlipidemias

Hyperlipoproteinemia	Synonyms	Problems	Labs description	Treatment
Type I	Buerger-Gruetz syndrome, primary hyperlipoproteinaemia, or familial hyperchylomicronemia	Decreased lipoprotein lipase (LPL) or altered ApoC2	Elevated chylomicrons	Diet control
Type IIa	Polygenic hypercholesterolaemia or familial hypercholesterolemia	LDL receptor deficiency	Elevated LDL only	Bile acid sequestrants, statins, niacin
Type IIb	Combined hyperlipidemia	Decreased LDL receptor and increased ApoB	Elevated LDL, VLDL and triglycerides	Statins, niacin, gemfibrozil
Type III	Familial Dysbetalipoproteinemia	Defect in ApoE synthesis	Increased IDL	Drug of choice: Gemfibrozil
Type IV	Endogenous Hyperlipemia	Increased VLDL production and decreased elimination	Increased VLDL	Drug of choice: Niacin
Type V	Familial Hypertriglyceridemia	Increased VLDL production and decreased LPL	Increased VLDL and chylomicrons	Niacin, gemfibrozil

Unclassified forms

Non-classified forms are extremely rare:

• Hypo-alpha lipoproteinemia
• Hypo-beta lipoproteinemia (prevalence 0.01-0.1%)

Classification According to Etiology

Lipoprotein/Lipid disorders

Primary (Genetic)

Secondary

LDL

Chylomicron Remnants

Lipoproteins Rich in Triglyceride (Chylomicrons, VLDL, IDL)

HDL

Multiple lipoproteins

Alcohol Diabetes Drugs Liver disease Obesity Renal disease Smoking Thyroid

High LDL: -Familial hypercholesterolemia -Familial defective apo B 100 -Autosomal dominant hypercholesterolemia (PCSK9) -Autosomal recessive hypercholesterolemia -Familial sistosterolemia -Familial lipoprotein a lipoproteinemia Low LDL: -Abetalipoproteinemia -Hypobetalipoproteinemia -PCSK 9 deficiency

-Deficiency in hepatic lipase -Type III dysbetalipoproteinemia

-Deficiency in lipoprotein lipase -Deficiency in Apo C-II -Deficiency in Apo A-V -Familial combined hyperlipidemia -Familial hypertriglyceridemia - Chylomicron retention disease

High LDL: -Cholesteryl ester transferase protein deficiency Low HDL: -Deficiency in Apo A-I -Deficiency in lecithin cholesterol acyltransferase (LCAT) -Familial hypoalphalipoproteinemia -Nieman-Pick disease -Tangier disease

- Familial combined hypolipidemia (ANGPTL3)

Classification According to Laboratory Results

Lipid Laboratory Tests

Total cholesterol

LDL-C

HDL-C

Triglycerides

High total cholesterol

Low total cholesterol

High LDL

Low LDL

High HDL

Low HDL

High triglyceride

Low triglyceride

External links

• The Fredrickson papers (with photos from early lipoprotein research)