Familial hypercholesterolemia

Alternative names:

hypercholesterolemic xanthomatosis; type II hyperlipoproteinemia

Definition:

A dominantly inherited condition that results in elevated LDL (low-density lipoprotein) cholesterol levels beginning at birth, and resultant myocardial infarctions (heart attacks) at an early age.

Causes, incidence, and risk factors:

Affected people have consistently high levels of low-density lipoprotein, which leads to premature atherosclerosis of the coronary arteries. Typically in affected men, acute myocardial infarctions (heart attacks) occur in their 40s to 50s, and 85% of men with this disorder have experienced a heart attack by age 60. The incidence of heart attacks in women with this disorder is also increased, but delayed 10 years later than in men.

Individuals from families with a strong history of early heart attacks should be evaluated with a lipid screen. Proper diet, exercise, and the use of newer drugs can bring lipids down to safer levels.

It is possible for a person to inherit two genes for this disorder. This magnifies the severity of the condition. Cholesterol values may exceed 600 mg/cc. Affected individuals develop waxy plaques (xanthomas) beneath the skin over their elbows, knees, buttocks. These are deposits of cholesterol in the skin. In addition they develop deposits in tendons and around the cornea of the eye. Atherosclerosis begins before puberty and heart attacks and death may occur before age 30. Little of therapeutic value is presently available for this condition.

The incidence of familial hypercholesterolemia is 7 out of 1000 people.