Familial hypercholesterolaemia (FH) is an inherited genetic condition that results in markedly elevated low-density lipoprotein (LDL or "bad") cholesterol levels, beginning at birth.
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FH changes the way the body handles cholesterol. Your genes can give you cells that don't remove LDL cholesterol from your blood efficiently, or a liver that produces too much cholesterol.
A consequence of FH is often the early development of problems such as premature atherosclerosis, which translates directly into heart problems.
The goal of treatment is to reduce the risk of atherosclerotic heart disease and heart attack by means of lifestyle changes and/or medication.
If you have a family history of cholesterol problems or cardiovascular disease, regardless of your age, you should consult your doctor for a full fasting lipogram.
Alternative names
Type II hyperlipoproteinaemia; hypercholesterolaemic xanthomatosis; low-density lipoprotein receptor mutation.
What is familial hypercholesterolaemia?
Familial hypercholesterolaemia (FH) is an inherited genetic condition that results in markedly elevated low-density lipoprotein (LDL or "bad") cholesterol levels, beginning at birth. The condition may result in heart attacks at an early age.
FH is surprisingly common among the Afrikaans population, with an incidence of around one in 75. This is because the disease arrived in South Africa with one Huguenot couple and spread from them. The disease also occurs in all the other South African population groups with the lowest incidence in the black community.
What causes it?
FH is caused by an inherited (genetic) problem that changes the way the body handles cholesterol. Your genes can give you cells that don't remove LDL cholesterol from your blood efficiently, or a liver that produces too much cholesterol. In such cases, a person's total cholesterol will usually be well over 6.5 mmol/L.
It is inherited in a dominant fashion which means that the presence of a single FH gene from one affected parent can produce the condition in the child who inherits it – that is, in an average of 50% of the offspring.
Much more rarely, an individual inherits an FH gene from two affected parents. This is called the homozygous condition and is much more severe, with coronary artery disease (CAD) generally present by the age of 20.
What are the symptoms?
A consequence of FH is often the early development of problems such as premature atherosclerosis, which translates directly into heart problems.
Warning signs and symptoms of FH include:
a strong family history of FH or early heart attack;
high, therapy-resistant levels of LDL cholesterol in either or both parents;
yellowish skin lesions (xanthomas);
cholesterol deposits in the eyelids (xanthelasmas);
chest pain (angina); and
obesity.
How is it diagnosed?
In a person with the gene for FH, cholesterol levels (mainly LDL cholesterol) are raised from birth making early diagnosis possible. However, clinical disease usually shows itself only in adulthood.
Diagnosis can often be made clinically and from routine laboratory measurements, but molecular techniques now permit definite identification of affected individuals and prenatal testing.
How is it treated?
The goal of treatment is to reduce the risk of atherosclerotic heart disease and heart attack.
The first step is to adopt a well-balanced diet for a few months, aimed at lowering cholesterol, trans-fat and total fat intake (consultation with a registered dietician is highly recommended). Such a diet will entail:
eating less beef, pork, lamb and organ meat;
removing the skin from chicken;
switching to fat-free dairy products;
spreading only "lite" margarine on bread;
steering clear of commercially prepared crisps, crackers and cookies as well as deep-fried foods; and
eliminating coconut and palm oil.
The second step is to do more physical exercise if a medical doctor gives the green light.
The third step involves drug therapy. Medication may be required if diet, exercise, and weight-loss efforts don't succeed in lowering cholesterol. Various cholesterol-reducing agents are available. These include:
Bile acid sequestrant resins (cholestyramine and colestipol)
Nicotinic acid (niacin)
Statin drugs
Gemfibrozil
Fenofibrate
What is the prognosis?
Unfortunately, the prognosis is poor for people who have the treatment-resistant, homozygote-type of FH This inevitably leads to early heart attack.
The outcome of other types of FH depends largely on compliance with treatment, but reduction in serum cholesterol levels can be achieved which may succeed in delaying a heart attack.
When to call your doctor
If you have a family history of cholesterol problems or cardiovascular disease, regardless of your age, you should consult your doctor for a full fasting lipogram. You may have no symptoms at all and still have raised cholesterol levels, which can be treated before there are permanent problems.
How can it be prevented?
In families where both parents have been diagnosed with FH, counselling may be beneficial. Heart attacks may be prevented or delayed by early diagnosis and appropriate treatment.
(Carine van Rooyen, Health24, January 2008)
Source: National Institutes of Health (www.nih.gov)
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