What is familial hypercholesterolaemia?
Familial hypercholesterolaemia is inherited high cholesterol. It 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.
What causes familial hypercholesterolaemia?
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.
What are the features of familial hypercholesterolaemia
- 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.
- Xanthelasma - fatty deposits in the eyelids.
- Arcus senilis - a white ring around the cornea (the coloured part of the eye).
How is familial hypercholesterolaemia diagnosed?
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:
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.
What are the aims of treatment?
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.
What are the treatment options for familial hypercholesterolaemia?
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:
- Healthy eating: in general it's a good idea to eat healthily. But it's important to note that what you eat makes hardly any difference to your cholesterol level.
- Getting a reasonable amount of exercise.
- Avoiding smoking: this is vital if you have high cholesterol.
- Maintaining a normal weight: but slim people can have a high cholesterol too. Being overweight doesn't cause high cholesterol.
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.
What is the outlook?
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.
Did you find this information useful?
- Lipid modification - cardiovascular risk assessment and the modification of blood lipids for the prevention of primary and secondary cardiovascular disease; NICE Clinical Guideline (July 2014)
- 2016 European Guidelines on cardiovascular disease prevention in clinical practice; European Society of Cardiology (2016)
- Identification and management of familial hypercholesterolaemia; NICE Clinical Guideline (August 2008 - last updated July 2016)
- Simon Broome Diagnostic criteria for index individuals and relatives - Appendix F; NICE (2008)
- 2016 ESC/EAS Guidelines for the Management of Dyslipidaemias; European Society of Cardiology (2016)
- Report of the Joint British Societies for the Prevention of Cardiovascular Disease; JBS3, 2014
- de Souza RJ, Mente A, Maroleanu A, et al; Intake of saturated and trans unsaturated fatty acids and risk of all cause mortality, cardiovascular disease, and type 2 diabetes: systematic review and meta-analysis of observational studies. BMJ. 2015 Aug 11 351:h3978. doi: 10.1136/bmj.h3978.
- Linton MF, Yancey PG, Davies SS, et al; The Role of Lipids and Lipoproteins in Atherosclerosis
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