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

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Lipoprotein disorders can be classified according to the Fredrickson classification which is based on the pattern of lipoproteins on electrophoresis or ultracentrifugation.[1] 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 It remains a popular system of classification, but is considered outdated by many.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

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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

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| Hyperlipoproteinemia/Hyperlipidemia|

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| 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

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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

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Non-classified forms are extremely rare:

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

### Classification According to Etiology

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| Lipoprotein/Lipid disorders|

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| 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

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| Lipid Laboratory Tests|

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| 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

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

## References

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1. ↑ Frederickson DS, Lee RS. A system for phenotyping hyperlipidemia. Circulation 1965;31:321-7. PMID 14262568.

* v
* t
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Lipopedia

Basic Science|

Cholesterol • Triglyceride

Lipoprotein metabolism and transport

Lipoprotein: Chylomicron • Chylomicron remnant • HDL • IDL • LDL • Lipoprotein(a) • VLDL • Lipoprotein-X

Apolipoprotein: APOA (1, 2, 4,  5) • APOB ( Apolipoprotein B-48, Apolipoprotein B-100) • APOC (1, 2, 3, 4) • APOD • APOE • APOH • APOJ • APOL • APOM • Apo(a)

Lipoprotein receptor: LDL receptor • Soluble low density lipoprotein receptor-related protein (sLRP) • Apolipoprotein E Receptor 2 • Scavenger receptor • Scavenger receptor A • Scavenger receptor B • VLDL receptor

Lipoprotein enzymes: Lipoprotein lipase • Lipoprotein-associated phospholipase A2 (Lp-PLA2) • Cholesterylester transfer protein ( Acetyl-CoA C-acyltransferase, Lecithin-cholesterol acyltransferase) • Microsomal triglyceride transfer protein • ABCA1

Genes: Low density lipoprotein receptor gene family • Microsomal triglyceride transfer protein • ABCA1

Lipoprotein Disorders|

Lipoprotein disorders

Primary lipoprotein disorders: Familial hyperchylomicronemia (Type I) • Familial hypercholesterolemia (Type IIA) • Familial combined hyperlipidemia (Type IIB) • Dysbetalipoproteinemia (Type III) • Primary hypertriglyceridemia (Type IV) • Mixed hyperlipoproteinemia (Type V)

Secondary lipoprotein disorders

Abnormal Laboratory Lipid Profile|

Low chylomicron • Low chylomicron remnant • Low HDL • Low IDL • Low LDL • Low lipoprotein(a) • Low VLDL

High chylomicron • High chylomicron remnant • High HDL • High IDL • High LDL • High Lipoprotein(a) • High VLDL

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