You've tried everything to lower your high cholesterol, including eating a diet low in saturated fats, exercising regularly, and increasing your fiber intake. Still, your cholesterol refuses to budge. You may have what's called familial hypercholesterolemia (FH).
FH is the best understood lipid abnormality and probably the most common of all inherited disorders. The disorder is caused by an abnormality in the receptor for low density lipoprotein (LDL) that results in poor removal of LDL from the blood.
Usually, half of the children of a parent with this abnormality will inherit an abnormal form of the gene for the LDL receptor. While only one in a million people in the U.S. will inherit an FH gene from both parents (homozygotes), one in every 500 people in this country will get it from only one parent (heterozygotes).
LDL cholesterol levels in people with FH can exceed 1000 mg/dL in homozygotes and range from 300 to 600 mg/dL in heterozygotes. Homozygotes usually die of coronary artery disease and narrowing of their aortic valve before the age of 20. Left untreated, heterozygotes begin to have heart attacks 10 to 15 years earlier than unaffected men and women.
Generally, FH is suspected when a person has high cholesterol coupled with a family history of both high cholesterol and premature coronary artery disease. Children with FH have high cholesterol levels at birth. Later in life, the diagnosis can be confirmed with near certainty when there is thickening of the Achilles tendons or lumps in other tendons.
Doctors usually begin treating FH with a low-fat, low-cholesterol diet, but people with this disorder don't respond well, if at all, to these dietary measures. Statins are usually the most effective drugs to lower cholesterol. Because they work by increasing the number of LDL receptors, however, statins don't work in homozygotes, whose LDL receptors are either absent or defective. The best treatment for people with homozygous FH is to remove the LDL by plasmapheresis about every two weeks. In this procedure blood is withdrawn and separated into plasma and cells, and the cells are returned.
People with heterozygous FH usually respond to statins, though often not as well as other people. Their LDL cholesterol levels may be lowered further by blocking the body's absorption of cholesterol with ezetimibe (Zetia) or bile acids with a bile acid sequestrant such as cholestyramine (Questran), colestipol (Colestid), or colesevelam (Welchol).
If you think you or your children may have FH, it's critical to recognize and treat it as early as possible to prevent the almost inevitable development of coronary heart disease.
