An inherited disorder in which both cholesterol and triglycerides are elevated in the plasma.
Alternative Names
Type III hyperlipoproteinemia; Deficient or defective apolipoprotein E
Causes, incidence, and risk factors
Familial dysbetalipoproteinemia is caused by a gene defect that results in an accumulation of large lipoprotein particles that contain both cholesterol and triglyceride. The disease is inherited in an autosomal recessive manner and can be traced to defects in the gene for apolipoprotein E in many cases. The disease is usually not evident by elevated blood levels or symptoms until the age of 20 or later. Atherosclerosis develops in the coronary arteries, internal carotid arteries that supply blood to the brain, and the abdominal aorta and its branches. The condition predisposes people to coronary artery disease and peripheral vascular disease . The condition is worsened by hypothyroidism , obesity , or diabetes . Risk factors are a family history of familial dysbetalipoproteinemia or coronary artery disease. The incidence is 1 out of 10,000 people.
Signs and tests
a physical exam revealing characteristic xanthomas elevated serum LDL
significantly increased remnants of VLDL and chylomicrons elevated total cholesterol
elevated coronary risk profile triglycerides
increased liklihood of apoE2 genotype defective apoE protein atherosclerosis evident by angiogram abnormal heart stress test
Treatment
The goal of treatment is to control underlying conditions such as obesity , hypothyroidism , and diabetes that can make dysbetalipoproteinemia appear in people who would otherwise not have it. The restriction of excess calories and the reduction of saturated fats and cholesterol may significantly reduce cholesterol levels . If high cholesterol and triglyceride levels persist with maximum dietary treatment, cholesterol lowering agents should be started. Nicotinic acid ( niacin ), clofibrate, statins or gemfibrozil are drugs that have effectively reduced cholesterol and triglycerides in people affected with dysbetalipoproteinemia.
Expectations (prognosis)
Individuals with this form of hyperlipidemia have a significantly increased risk for coronary artery disease . With treatment, most people show a significant reduction in lipid levels.
Complications
premature myocardial infarction (heart tissue death)
strokes blocked arteries to the body (peripheral vascular disease) intermittent claudication
gangrene of the lower extremities xanthomas of the skin
Calling your health care provider
Call your health care provider if symptoms worsen, do not improve with treatment, or new symptoms develop. Call a genetic counselor if there is a family history of dysbetalipoproteinemia.
Prevention
Screening for family members of people 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.