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Familial Hypercholesterolaemia

Familial Hypercholesterolaemia

Familial hypercholesterolaemia is a condition where your level of cholesterol is too high.  It runs in the family (doctors called this 'inherited'). It doesn't make you feel ill and is only picked up by chance in a routine blood test, or if you find you have small fatty bumps around your eyes or the back of your heels. If your cholesterol level is too high for a long time it can cause problems with your heart and cause a heart attack at a young age.  The treatment is to take medications that lower your cholesterol. Having a generally healthy lifestyle will also help.

Familial hypercholesterolaemia (inherited high cholesterol) is a condition where you have a very high cholesterol level in your blood. It is called familial because it runs in the family (the other word for this is 'inherited'). The condition affects about 1 in 500 people.

For more detail about the different types of cholesterol and what they do, see separate leaflet called Cholesterol.

We all have cholesterol in our blood; in fact, it is essential for our bodies to work properly. Usually it stays at a fairly low level because it is constantly made and then broken down again. But in hypercholesterolaemia the cholesterol isn't broken down properly, so the level goes too high. The problem lies in your genes: you can inherit one faulty 'cholesterol breakdown gene' from a parent, who you might then find out also has high cholesterol. (This is termed heterozygous inheritance.)  Occasionally you can inherit two faulty genes: one from each parent. (This is called homozygous inheritance.)  But this is rare.

Having a high cholesterol level doesn't make you feel ill. You won't know you have it without having a blood test.

The most important feature is the development of heart disease at a young age. This is caused by patches (plaques) of atheroma developing within the walls of the heart (coronary) arteries (see below). This can lead to a heart attack (myocardial infarction) as a young adult. You might also notice:

  • Xanthomas - fatty cholesterol-rich deposits in the skin, usually found around the elbows, knees, buttocks and tendons.
  • Xanthelasmas - fatty deposits in the eyelids.
  • Arcus senilis - a white ring around the cornea (the coloured part of the eye).
Diagram of an artery showing patches of atheroma

Patches of atheroma are like small fatty lumps that develop within the inside lining of blood vessels (arteries). Atheroma is also known as atherosclerosis and 'hardening' of the arteries. Patches of atheroma are often called plaques of atheroma. A main risk factor for developing atheroma is a high blood cholesterol level. Over months or years patches of atheroma can become larger and thicker. So, in time, a patch of atheroma can make an artery narrower. This can reduce the blood flow through the artery. For example, narrowing of the heart (coronary) arteries with atheroma is the cause of angina.

Sometimes a blood clot (thrombosis) forms over a patch of atheroma and completely blocks the blood flow. Depending on the artery affected, this can cause a heart attack (myocardial infarction) a stroke, or other serious problems.

Cardiovascular diseases are diseases of the heart muscle or blood vessels. When doctors say cardiovascular disease they usually mean diseases of the heart or blood vessels that are caused by atheroma. In summary, cardiovascular diseases that can be caused by atheroma include angina, heart attack, stroke, transient ischaemic attack (TIA), and peripheral arterial disease. In the UK, cardiovascular diseases are a major cause of poor health and they are the most common cause of death.

You may be diagnosed by chance if you go for a health screening check or you may notice fatty deposits on the skin or around the eyes.

Another member of your family may be diagnosed with familial hypercholesterolaemia or have a heart attack (myocardial infarction) before the age of 50, and you may be advised to have a check yourself. You will be advised to have a blood test to check your cholesterol. Familial hypercholesterolaemia is suspected in adults if the total cholesterol is 7.5 mmol/L or greater, or the LDL cholesterol (a particular type of cholesterol) is 4.9 mmol/L or greater. In children (between the ages of 10 and 15 years) the levels are 6.7 mmol/L and 4.0 mmol/L respectively.

This photo shows the typical signs of high cholesterol around the eyes: these pale deposits are called xanthelasma.

Xanthelasma

There are more detailed ways of diagnosing familial hypercholesterolaemia, using the 'Broome criteria'.  These take into account your cholesterol level; the levels of first-degree and second-degree relatives; signs of cholesterol build-up on tendons; and some detailed genetic tests.  You can read more about the Broome criteria in the National Institute for Health and Care Excellence (NICE) guidelines in the further reading section.

You are unlikely to have any symptoms from familial hypercholesterolaemia as a child or young adult. However, you should be treated to stop symptoms and complications from developing when you are older - the most important of these being heart disease that may develop at an earlier age than usual.

Being a genetic disorder, familial hypercholesterolaemia is not caused by an unhealthy lifestyle. However, keeping yourself in the best physical condition will help to prevent future problems.

Things you can do to help yourself include:

You will be offered medication to help bring your cholesterol level down. The usual medicine to start with is a statin. The most common statin used is called simvastatin. If the level does not come down, another medicine called ezetimibe is sometimes added.

Affected children usually start statin medication in late childhood or early adolescence. Some children may need apheresis. This is a treatment which filters LDL cholesterol out of the blood. It is offered to those who have the greatest risk of developing problems - in particular, those with the rare form of familial hypercholesterolaemia where they have inherited a faulty gene from each parent.

Your GP may want to discuss referring you to a specialist. A specialist can advise about your treatment and arrange the testing of close members of your family.

The outlook (prognosis) for people with heterozygous familial hypercholesterolaemia is usually good if they maintain a healthy lifestyle, have regular checks and take their medication without fail. The most significant complication is heart disease or another cardiovascular disease that may develop at a younger age than usual.

Further reading & references

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. Patient Platform Limited has used all reasonable care in compiling the information but makes no warranty as to its accuracy. Consult a doctor or other healthcare professional for diagnosis and treatment of medical conditions. For details see our conditions.

Author:
Dr Oliver Starr
Peer Reviewer:
Dr Jacqueline Payne
Document ID:
12232 (v4)
Last Checked:
01/08/2017
Next Review:
31/07/2020