Definition Familial hypercholesterolaemia is an inherited disease that causes high cholesterol levels.
What is going on in the body? Normally, the liver regulates the amount of cholesterol or fat in the blood. It uses special docking sites, or receptors, to remove extra cholesterol. A person with familial hypercholesterolaemia inherits an abnormal gene for the docking site from one or both parents.
If an abnormal gene is inherited from one parent, the body makes only half of the usual number of docking sites. If the abnormal gene is inherited from both parents, the body makes no docking sites. In either case, the level of cholesterol gets too high in the blood. This can lead to heart attacks, strokes, and other problems.
What are the signs and symptoms of the condition? One of the main health issues with any cholesterol problem is that there are often no obvious symptoms of the condition before the development of coronary artery disease.
Because of the very high cholesterol levels, many people with this disease develop cholesterol deposits in the skin. These are often seen on the:
knuckles of the hand
What are the causes and risks of the condition? This disease is inherited and occurs in about 1 in 1000 people. The chance of inheriting two bad genes, one from each parent, is 1 in 1,000,000.
What can be done to prevent the condition? An inherited trait cannot be prevented. Genetic counselling may be useful to couples with a family history of the disease.
How is the condition diagnosed? This disease is diagnosed by a blood test and family history. Cholesterol levels are low at birth and increase with age. Levels over 7mmol/L (milliomoles per litre) are associated with a higher risk of heart attacks, strokes, and other health problems. The accepted cholesterol level is dependent on a number of factors such as age, a past medical history of diabetes, IHD, stroke etc. The aim of a healthy individual without a significant past medical history is to achieve a cholesterol level below 5.5 mmol/L.
What are the long-term effects of the condition? A person with this disease generally develops artery blockages at an early age. For example, by age 50, a person with this condition is 3 to 10 times more likely than normal to have a heart attack. Heart disease, strokes, and other problems may also occur.
Because of the very high risk of heart attacks, diagnosis and treatment should begin as soon as possible.
What are the risks to others? This condition is inherited and is not contagious. Children and other family members of affected people should have cholesterol screening. Early detection and treatment of this condition may delay the complications.
A person with one abnormal gene will need medications to lower the cholesterol level. Examples of medications used include bile acid resins, statin drugs, and niacin. Combinations of medications are often needed.
Someone with two abnormal genes is generally treated by an expert in this disease. The use of a machine to filter the blood may be the only good way to lower the cholesterol.
What are the side effects of the treatments? Since the liver makes cholesterol, most of the medications to lower cholesterol levels may affect the liver.
Specific side effects vary by the medication, and may include:
constipation with bile acid resins, such as cholestyramine and colestipol
flushing, itching and increased blood sugar with niacin
muscle aches with statin drugs, such as atorvastatin, fluvastatin, pravastatin, and simvastatin
What happens after treatment for the condition? Treatment is generally needed for life.
Author: Evan M. Sisson, Pharm.D., MHA, CDE Reviewer: eknowhow Medical Review Panel Editor: Dr John Hearne Last Updated: 22/11/2004 Contributors Potential conflict of interest information for reviewers available on request
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