It is not known how often sitosterolemia occurs. As of 2000, only about 40 people with sitosterolemia had been identified worldwide. It is thought that sitosterolemia is more often misdiagnosed as high blood cholesterol, one of the disease's effects in the body. The disease can become evident at any age.
Symptoms
There are several important symptoms of sitosterolemia:
- High level of plant sterols in the blood; blood cholesterol may be normal to high
- Lumps or bumps on the skin, called xanthomas. These often occur in the tendons of the hands and the Achilles tendons in the heel.
- Arthritis, particularly in the knees and ankles.
Diagnosis
Xanthomas and arthritis may be the first indications that a person has sitosterolemia. A special test can check the levels of cholesterol and plant sterols in the blood. Of sterols in the blood, cholesterol accounts for more than 99% and plant sterols about 0.2%. In sitosterolemia, cholesterol accounts for 80% and plant sterols about 20%. This high level of plant sterols in the blood would confirm the diagnosis.
Treatment
Once sitosterolemia is diagnosed, a diet low in plant sterols may be recommended. This would include:
- Eliminate all sources of vegetable fats, including nuts, seeds, olives, and avocados
- Eliminate vegetable oils, shortening, and margarine
- Eliminate chocolate (high in plant sterols)
In October 2002 a cholesterol absorption inhibitor, the drug ezetimibe (Zetia), received U.S. Food and Drug Administration approval for use in sitosterolemia. The drug reduces the level of plant sterols in the blood. Drugs such as cholestyramine (Prevalite, Questran) which bind with bile acids in the digestive system achieve similar results.
Information for this article was taken from:
Steiner, R. D. (2004). Sitosterolemia. eMedicine, accessed at http://www.emedicine.com/ped/topic2110.htm
