Genetics Northern California

Familial Combined Hyperlipidemia

Familial combined hyperlipidemia (FCH) is an inherited condition that leads to higher than normal amounts of several fatty substances in your blood: triglycerides, low density lipoprotein (LDL) and cholesterol. You can also have FCH even if only one of these substances is elevated. Conditions that cause changes in the amount of fatty substances are called lipid disorders. FCH is the most common type of inherited lipid disorder and affects 1 to 2% of the population. Having a lipid disorder increases your chance for coronary artery disease and can lead to heart attacks and strokes.

In addition to increasing the amount of total cholesterol and triglycerides, FCH also can cause changes in the balance of the different types of cholesterol in your body. Levels of high density lipoprotein (HDL or “good cholesterol”) are sometimes lowered, and the size of low density lipoproteins (LDL or “bad cholesterol”) is sometimes made smaller and denser. Both of these changes are additional risk factors for cardiovascular disease. Another feature of FCH is too much very low density lipoprotein (VLDL). VLDL is made in the body by combining certain proteins and fats, including a large amount of triglyceride. It is needed by the body to move around fats and cholesterol. The amount of VLDL in your body is determined, in part, by the amount of fat in your liver and the fat in your abdomen and around your organs (also known as “belly fat”).

Lipid disorders are due to a combination of your genes and your lifestyle. In FCH, genetic factors increase your triglyceride and cholesterol levels, even with a healthy diet and lifestyle. However, lifestyle can still impact your lipids. Obesity, poor eating habits, 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.

The specific genes that cause FCH are not known, but in many families the condition seems to follow a dominant inheritance pattern. If one parent has this condition, there is about 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”. When the inherited risk for FCH comes from both parents, it can cause severe coronary artery disease with medical problems starting as early as the late teens, compared to 40's to 60's in other family members.

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

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

Dietary strategies include:

  • Choose healthy fats in modest amounts  -  How Fats Compare

  • Choose complex higher fiber foods over refined carbohydrate foods – Fiber Facts

  • Adjust portion sizes for weight loss or control

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.  Read the label for the specific amount of EPA and DHA per capsule. Purchase fish oil capsules that have been molecularly distilled to remove contaminants.

In addition, the clinic staff members carefully evaluate whether available medication may be beneficial. If medications are indicated, the clinic staff will make recommendations as to the appropriate age to start and how on going follow-up should be managed. The clinic staff may also work with the parents and their primary care providers to optimize their treatment regimen when necessary.
 

Created by:      Suzanne Kordesh, MPH, RD
Reviewed by:     Suzanne Kordesh, MPH, RD,
                        Kimberly Barr, MS, CGC
                        Emily Chen, MD PhD


Last Reviewed: 5/11/10
Last Updated: 5/11/10