Familial hypercholesterolemia: Description:
Alternative Names: Type II hyperlipoproteinemia; Hypercholesterolemic xanthomatosis; Low density lipoprotein receptor mutation.
Familial hypercholesterolemia is a condition passed down through families in which a person has high levels of "bad" cholesterol (low density lipoprotein, or LDL) beginning at birth. The condition can cause heart attacks at an early age.
To understand high blood cholesterol, it is important to know more about cholesterol. Cholesterol is a waxy, fat-like substance that is found in all cells of the body. Your body needs some cholesterol to work the right way. Your body makes all the cholesterol it needs. Cholesterol is also found in some of the foods you eat. Your body uses cholesterol to make hormones, vitamin D, and substances that help you digest foods.
Blood is watery, and cholesterol is fatty. Just like oil and water, the two do not mix. To travel in the bloodstream, cholesterol is carried in small packages called lipoproteins. The small packages are made of fat (lipid) on the inside and proteins on the outside. Two kinds of lipoproteins carry cholesterol throughout your body. It is important to have healthy levels of both:
- Low-density lipoprotein (LDL) cholesterol is sometimes called bad cholesterol. High LDL cholesterol leads to a buildup of cholesterol in arteries. The higher the LDL level in your blood, the greater chance you have of getting heart disease.
- High-density lipoprotein (HDL) cholesterol is sometimes called good cholesterol. HDL carries cholesterol from other parts of your body back to your liver. The liver removes the cholesterol from your body. The higher your HDL cholesterol level, the lower your chance of getting heart disease.
Familial hypercholesterolemia is caused by a gene defect on chromosome 19. The defect makes the body unable to remove LDL cholesterol from the bloodstream. This results in consistently high levels of LDL in the blood, which leads to atherosclerosis at an early age.
The condition is typically passed down through families in an autosomal dominant manner. That means you only need to get the abnormal gene from one parent in order to inherit the disease. An individual who inherits one copy of the gene is considered "heterozygous."
In rare cases, a child may inherit the gene from both parents. Individuals who inherit both genes are considered "homozygous." Homozygous familial hypercholesterolemia is much more severe. Cholesterol levels may exceed 600mg/dL, greatly increasing the risk for heart attacks and heart disease.
Men who have familial hypercholesterolemia have heart attacks in their 40's to 50's, and 85 percent of men with the disorder have a heart attack by age 60. Women who have familial hypercholesterolemia also have an increased risk for heart attack, but it happens 10 years later than in men.
Familial hypercholesterolemia is inherited in families in an autosomal dominant manner. In autosomal dominant inherited conditions, a parent who carries an altered gene that causes the condition has a 1 in 2 (50 percent) chance to pass on that altered gene to each of his or her children.
A diet low in cholesterol and saturated fat and rich in unsaturated fat diet may help to control LDL levels. Counseling is an option for those who have a family history of this condition, particularly if both parents carry the defective gene.
The major symptoms and signs of familial hypercholesterolemia are:
Causes and Risk factors:
- High levels of total cholesterol and LDL cholesterol.
- A strong family history of high levels of total and LDL cholesterol and/or early heart attack.
- Elevated and therapy-resistant levels of LDL in either or both parents.
- Xanthomas (waxy deposits of cholesterol in the skin or tendons).
- Xanthelasmas (cholesterol deposits in the eyelids).
- Corneal arcus (cholesterol deposit around the cornea of the eye).
- If angina (chest pain) is present may be sign that heart disease is present.
Hypercholesterolemia Familial (FH) can occur in either the heterozygous or homozygous state, with 1 or 2 mutant LDLR LDL receptor gene) allelesAny one of a series of two or more different genes that may occupy the same locus on a specific chromosome. As autosomal chromosomes are paired, each autosomal gene is represented twice in normal somatic cells. If the same allele occupies both units of the locus, the individual or cell is homozygous for this allele. If the alleles are different, the individual or cell is heterozygous for both alleles), respectively. In general, FH heterozygotes have 2-fold elevations in plasma cholesterol and develop coronary atherosclerosis after the age of 30. Homozygous FH individuals have severe hypercholesterolemia (>650 mg/dL) with the presence of cutaneous xanthomas prior to 4 years of age, childhood coronary heart disease, and death from myocardial infarction prior to 20 years of age. Heterozygous FH is prevalent among many different populations, with an approximate average worldwide incidence of 1 in 500 individuals, but as high as 1 in 67 to 1 in 100 individuals in some South African populations and 1 in 270 in the French Canadian population. Homozygous FH occurs at a frequency of approximately 1 in 1,000,000.
Check the list to see how many of the risk factors you have. These are the risk factors that affect your LDL goal:
A physical examination may reveal fatty skin growths called xanthomas and cholesterol deposits in the eye (corneal arcus).
Other signs include:
- Cigarette smoking.
- High blood pressure (140/90 mg/dL or higher), or if you are on blood pressure medicine.
- Low high-density lipoprotein (HDL) cholesterol (less than 40 mg/dL).
- Family history of early heart disease (heart disease in father or brother before age 55; heart disease in mother or sister before age 65).
- Age (men 45 years or older; women 55 years or older).
Individuals from families with a strong history of early heart attacks should have blood tests done to determine lipid levels. Blood tests may show:
- A strong family history of familial hypercholesterolemia or early heart attacks.
- High levels of LDL in either or both parents.
Other tests that may be done include:
- High levels of total cholesterol greater than 300 mg/dL in adults, greater than 250 mg/dL in children.
- LDL greater than 200 mg/dL.
- High level of triglycerides.
- Heart function (stress) test.
- Studies of cells called fibroblasts to see how the body absorbs LDL cholesterol.
- Genetic test for the defect associated with this condition.
The overall goal of treatment is to lower the risk for atherosclerotic heart disease by lowering the LDL cholesterol levels in the blood stream.
The first step in treatment for an individual who has heterozygous familial hypercholesterolemia is changing the diet to reduce the total amount of fat eaten to 30 percent of the total daily calories. This can be done by limiting the amount of beef, pork, and lamb in the diet; cutting out butter, whole milk and fatty cheeses as well as some oils like coconut and palm oils; and eliminating egg yolks, organ meats and other sources of saturated fat from animals. Dietary counseling is often recommended to help people to make these changes in their eating habits.
Exercise, especially to lose weight, may also help in lowering cholesterol levels.
Drug therapy is usually necessary in combination with diet, weight loss, and exercise, as these interventions may not be able to lower cholesterol levels alone. There are a number of cholesterol-lowering medications that are currently used. The first and more effective choice are drugs called "statins." Other drugs that may be used in combination with or instead of the statins are: bile acid sequestrant resins (for example, cholestyramine), ezetimibe, nicotinic acid (niacin), gemfibrozil, and fenofibrate.
Individuals who have homozygous familial hypercholesterolemia need more aggressive therapies to treat their significantly elevated levels of cholesterol. Often drug therapies are not sufficient to lower LDL cholesterol levels at the desiderated goal and these individuals may require periodical LDL apheresis, a procedure to "clean up" LDL from the blood stream, or highly invasive surgery such as a liver transplant.
Proper diet, exercise, and certain medications can bring lipids (fats in the blood) down to safer levels and reduce your risk of heart disease and heart attacks. Those who inherit only one copy of the defective gene may respond well to diet changes combined with statin drugs.
You can reduce fat intake by:
- Eating less beef, pork, and lamb.
- Choosing low-fat dairy products.
- Avoiding coconut and palm oil.
Cholesterol intake is reduced by avoiding:
- Egg yolks.
- Organ meats.
- Sources of animal-derived saturated fat.
Exercise, especially to induce weight loss, may also aid in lowering cholesterol levels.
Drug therapy may be started if diet, exercise, and weight-loss efforts have not lowered your cholesterol levels over time. Several cholesterol-lowering drugs are available, including:
- Bile acid sequestrant resins (cholestyramine and colestipol).
- Nicotinic acid (niacin).
- Statin drugs.
In rare cases, persons who inherited two copies of the defective gene may need surgery such as a liver transplant.
Medicine and medications:
Many people with this condition will require one or more medications as well, which may include:
- Statin drugs, such as Lipitor (atorvastatin), Zocor (simvastatin), Mevacor (lovastatin), Pravachol (pravastatin) or Crestor (rosuvastatin), which work by interfering with a liver enzyme required for cholesterol production.
- Zetia (ezetimibe), which blocks the absorption of cholesterol in the intestine.
- Nicotinic acid drugs (including Niaspan and Niacor), which lower LDL cholesterol, as well as raising blood levels of the "good" cholesterol called "HDL-C"
- Bile acid resins, such as Questran (cholestyramine) and Colestid (colestipol), which bind to bile acids in the intestine after which the entire compound is eliminated in the stool. Since the bile acids contain cholesterol, this results in the elimination of cholesterol from the body.
: The following drugs and medications are in some way related to, or used in the treatment. This service should be used as a supplement to, and NOT a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners.
DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.