Definition of Familial hypercholesterolemia:

Familial hypercholesterolemia is a disorder of high LDL ("bad") cholesterol that is passed down through families, which means it is inherited. The condition begins at birth and can cause heart attacks at an early age.

See also:

• Familial combined hyperlipidemia
• Familial hypertriglyceridemia
• Familial dysbetalipoproteinemia

Causes, incidence, and risk factors:

Familial hypercholesterolemia is a genetic disorder caused by a defect on chromosome 19.

The defect makes the body unable to remove low density lipoprotein (LDL, or "bad") cholesterol from the blood. This results in high levels of LDL in the blood. High levels of LDL cholesterol make you more likely to have narrowing of the arteries from atherosclerosis at an early age. Those with familial hypercholesterolemia are more likely to have a family history of high cholesterol and heart disease at a younger age than normal.

The condition is typically passed down through families in an autosomal dominant manner. That means you only need to get the abnormal gene from one parent in order to inherit the disease.

In rare cases, a child may inherit the gene from both parents.When this occurs, the increase in cholesterol levels is much more severe, greatly increasing the risk for heart attacks and heart disease.