Deficient or defective apolipoprotein E
Key points
- Familial dysbetalipoproteinemia is an inherited disorder in which both cholesterol and triglycerides are elevated in the plasma.
- The condition is caused by a gene defect that results in an accumulation of large lipoprotein particles that contain both cholesterol and triglyceride.
- 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.
- Individuals with this form of hyperlipidemia have a significantly increased risk for coronary artery disease.
Alternative names
Type III hyperlipoproteinemia; Familial dysbetalipoproteinemia
Definition
Familial dysbetalipoproteinemia is an inherited disorder in which both cholesterol and triglycerides are elevated in the plasma.
Causes, incidence, and risk factors
The condition 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.
Symptoms
- Yellow deposits of fatty material in the skin called xanthomas may appear on the palm of the hand, sole of the foot, or on tendons of knees and elbows, and on the eyelids.
- There may be early chest pain (angina) or decreased blood flow to other parts of the body, causing transient ischemic attacks of the brain or claudication of the legs.
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 profiletriglycerides
- 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.
Written and revised by
Gerald Hurowitz, M.D.
Our doctors write and review articles for accuracy and keep them up to date.
health.am provides general information, not medical advice. Always consult a qualified health professional about your own health.