Familial chylomicronemia syndrome (FCS) is a rare genetic disorder estimated to affect 1-2 individuals per million. It is a serious disease that prevents the body from breaking down fats consumed through the diet, or triglycerides. These triglycerides are carried in the blood by large structures called chylomicrons. Chylomicrons help move triglycerides to different parts of the body where they are needed for energy and fat storage.
While several genetic causes have been associated with FCS, about 80% of people with FCS have a problem with lipoprotein lipase. Lipoprotein lipase is a digestive enzyme in the blood that helps the body break down chylomicrons. People who have FCS are either unable to make lipoprotein lipase, or have a broken form of it. When lipoprotein lipase is absent or not working properly, chylomicrons build up in the blood, and triglyceride levels rise.
Normal triglyceride levels in the blood are less than 150 mg/dL. With FCS, it is not uncommon for triglyceride levels to exceed 1,000 mg/dL, even after medications and/or a low-fat diet are introduced.
Because FCS is an inherited disorder, symptoms and signs can develop as early as infancy or childhood, and commonly by adolescence. Some patients will not present with symptoms until adulthood. Common signs include:
Acute pancreatitis is the most serious complication of FCS and can occur repeatedly. It can lead to long-term pancreatic dysfunction and may be fatal if untreated. Patients with FCS are at a higher risk of developing pancreatitis compared to individuals with high triglycerides from other causes. Thus, one of the main goals of treatment is to reduce this risk as much as possible.
If a physician suspects FCS, genetic testing can be performed to confirm the diagnosis. However, cost and access to genetic testing may limit its use. Regardless of whether or not genetic testing is performed, appropriate management should be implemented when FCS is suspected.
Management involves limiting daily fat intake to less than 15 to 20 grams (less than 10-15% of total daily calories). Avoidance of alcohol and simple, refined carbohydrates, such as those found in sodas and candy, are also very important for preventing further rises in triglycerides. Certain medications can also raise triglyceride levels. It is important to discuss your medications with your doctor to determine if any may need to be discontinued. If you have diabetes, it is important that it be well-controlled
Traditional medications used to lower triglycerides are often ineffective in patients with FCS. So far, no medications have been approved for treatment of FCS, specifically.
If you suspect that you or a loved one has FCS, find a physician who can diagnose you and help you understand FCS. This is the most important step you can take to receiving the appropriate care. FCS is rare and often misdiagnosed, so document your symptoms and share them with your provider. Learn about FCS by seeking patient resources and educating yourself and community about this condition.
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