Dysbetalipoproteinemia

Lipoprotein Disorders Microchapters
Patient Information
Overview
Causes
Classification Hyperlipoproteinemia Hypolipoproteinemia
Treatment

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Synonyms and keywords: Broad beta disease; broad beta hyperlipoproteinemia; broad-beta hyperlipoproteinemia; dysbetalipoproteinemia; familial dysbetalipoproteinemia; familial hypercholesterolemia with hyperlipemia; type III hyperlipoproteinemia

Overview

Familial dysbetalipoproteinemia is a disorder passed down through families in which there are high amounts of cholesterol and triglycerides in the blood. This form is due to high chylomicrons and IDL (intermediate density lipoprotein). Also known as broad beta disease or dysbetalipoproteinemia, the most common cause for this form is the presence of ApoE E2/E2 genotype. It is due to cholesterol-rich VLDL (β-VLDL). Prevalence is 0.02% of the population.

Hyperlipoproteinemia type III, also known as dysbetalipoproteinemia or broad beta disease, is a rare genetic disorder characterized by improper breakdown (metabolism) of certain fatty materials known as lipids, specifically cholesterol and triglycerides. This results in the abnormal accumulation of lipids in the body (hyperlipidemia). Affected individuals may develop multiple yellowish, lipid-filled bumps (papules) or plaques on the skin (xanthomas). Affected individuals may also develop the buildup of fatty materials in the blood vessels (artherosclerosis) potentially obstructing blood flow and resulting in coronary heart disease or peripheral vascular disease. Most cases of hyperlipoproteinemia type III are inherited as an autosomal recessive trait.

Causes

A genetic defect causes this condition. The defect results in the build up of large lipoprotein particles that contain both cholesterol and triglycerides, a type of fat. The disease is linked to defects in the gene for apolipoprotein E in many cases.

Hypothyroidism, obesity, or diabetes can make the condition worse. Risk factors for familial dysbetalipoproteinemia include a family history of the disorder or coronary artery disease.

Symptoms

Symptoms may not be seen until age 20 or older.

Yellow deposits of fatty material in the skin called xanthomas may appear on the eyelids, palms of the hands, soles of the feet, or on the tendons of the knees and elbows.

Atherosclerosis develops. There may be early chest pain (angina) or decreased blood flow to specific parts of the body, causing transient ischemic attacks of the brain or peripheral artery disease.

Exams and Tests

Tests that may be done to diagnose this condition include:

• Angiogram
• Genetic testing for apolipoprotein E (apoE)
• Heart stress test
• Total cholesterol
• Triglyceride level
• Very low density lipoprotein (VLDL) test

Treatment

The goal of treatment is to control underlying conditions such as obesity, hypothyroidism, and diabetes.

Reducing calories, saturated fats, and cholesterol may significantly reduce cholesterol levels.

If high cholesterol and triglyceride levels continue despite diet changes, your doctor may recommend medicine to lower your cholesterol. Medicine to lower cholesterol levels include:

• Bile acid-sequestering resins
• Fibrates
• Nicotinic acid
• Statins

Prognosis

Persons with this condition have an increased risk for coronary artery disease and peripheral vascular disease.

With treatment, most people show a significant reduction in lipid levels.

Possible Complications

• Heart attack
• Stroke
• Peripheral vascular disease
• Intermittent claudication
• Gangrene of the lower extremities

Prevention

Screening the family members of those with familial dysbetalipoproteinemia may lead to early detection and treatment.

Early treatment and avoiding other risk factors for vascular disease (such as smoking) are crucial to preventing early heart attacks, strokes, and blocked blood vessels.