Genetics Northern California

Familial Combined Hyperlipidemia

Familial combined hyperlipidemia (FCH) is an inherited lipid disorder that leads to higher than normal levels of several types of fat in the blood: triglycerides, low density lipoprotein (LDL), and total cholesterol. A person can have FCH if one or two of these substances is elevated, however, people often show increases in all three.

FCH can also affect the normal balance of the two different types of cholesterol. The level of high density lipoprotein (HDL, or “good cholesterol”) is sometimes low, and the size of low density lipoproteins (LDL or “bad cholesterol”) are sometimes smaller and denser. Both of these changes add to the risk for cardiovascular (heart and blood vessel) disease.
Lipid disorders are due to a combination of genes and environmental factors, including lifestyle. In FCH, genetic factors increase triglyceride and cholesterol levels, even with a healthy diet and lifestyle. However, lifestyle still impacts lipids substantially. Obesity, poor eating habits, diabetes, and lack of exercise can make any inherited lipid disorder worse. Following a healthy diet and lifestyle can reduce the risk of cardiovascular disease even in someone with inherited risk factors. Even when medication is needed to change lipid levels, a healthy diet it is still protective for the heart and blood vessels.
The specific genes that cause FCH are not completely known, so genetic testing is generally not performed to make the diagnosis or treatment plan. A personalized management plan is based on the lipid profile and other medical factors. In many families the condition seems to follow a dominant inheritance pattern, meaning if one parent has this condition, there is a 50% chance that a child of that parent will inherit the genetic risk for FCH. If both parents have this lipid disorder, their children might inherit a “double dose,” which can cause medical problems and coronary artery disease much earlier in life.

Laboratory blood tests and family medical history are used to assess risk and treatment. The most commonly requested lipid laboratory tests are:

  • Cholesterol

  • Triglyceride

  • High Density Lipoprotein (HDL)

  • Low Density Lipoprotein (LDL)

A 12 hour fast is required for these tests. That means you have nothing to eat or drink, except plain water, before taking the test. 

Reference Range-Cholesterol.gif

Reference Range-Triglycerides

Reference Range-HDL Cholesterol.gif

Reference Range-LDL Cholesterol.gif

Reference Range-Lipoprotein.gif

The goal is the prevention of cardiovascular disease through appropriate healthy lifestyle changes, including diet and exercise.

Dietary strategies include:

  • Choose healthy fats in modest amounts

  • Choose complex higher fiber foods over refined carbohydrate foods
       Fiber Facts - Kaiser Permanente handout
       Whole Grain and Fiber - American Heart Association webpage

  • Focus on plant foods: The Plant Based Diet booklet

  • Adjust portion sizes for weight loss, if overweight

If you have high triglycerides, you may also benefit by eating more fish. Fatty fish like herring, sardines, albacore tuna and salmon are high in heart-healthy omega-3 fatty acids. Fish oil supplements can also be taken if recommended by your health care provider. The therapeutic dose is 1 to 3 grams of EPA/DHA per day. EPA and DHA are the fatty acids in fish oil that help lower triglycerides. Read the label for the specific amount of EPA and DHA per capsule to get the right dose. Purchase fish oil capsules that have been molecularly distilled to remove contaminants. Click here for more information on high triglycerides.

Created by:     Suzanne Kordesh, MPH, RD
Reviewed by:   Dr. Leslie Manace Brenman, MD,MPhil, Sub-Chief, Kaiser Permanente Northern California Genetics

Last Reviewed: January 2022