Inherited Raised Cholesterol
A high cholesterol level, a condition known as hypercholesterolemia, is typically caused by a poor diet and lifestyle combined with problems in the body’s ability to regulate lipid levels. But for some individuals (approx 1 in 500 of the population), high serum cholesterol is the result of a specific inherited genetic defect. Such a condition is called familial hypercholesterolemia (FH). If levels of triglycerides are also high, it is called familial combined hyperlipidemia (FCH). Patients with familial hypercholesterolemia (FH) have insufficient low-density lipoprotein (LDL) receptors that clear cholesterol from the bloodstream.
When Does Familial Hypercholesterolemia Occur?
In those who inherit this LDL-receptor genetic deficiency, elevated cholesterol levels in the blood are present from birth and this leads to an early development of atherosclerosis (narrowing of the arteries) and vascular diseases.
What Are The Chances Of Inheriting High Cholesterol?
Children of a person with FH have a 50 per cent risk of developing the condition. Fortunately, however, FH does not skip generations, so children and grandchildren of family members who do not have the defective gene in question are not at risk from the condition.
How Does Familial Hypercholesterolemia Develop?
Located in all the cells of the body (especially in the liver) is a receptor that facilitates removal of LDL (bad) cholesterol from the bloodstream. Thus patients whose cells do not have these receptors experience a build-up of LDL-cholesterol in the blood and ultimately in the arterial vessel wall – a process known as atherosclerosis.
What Are The Symptoms Of Familial Hypercholesterolemia?
People with FH do not know they have raised cholesterol, but there may be one or two visible signs. These include: cholesterol deposits in the tendons (xanthoma), for example, the Achilles tendon, or in the skin around the eyelids (xanthelasma palpabrum), or cornea of the eye (arcus senilis). In addition, a family history of elevated cholesterol levels and/or premature coronary artery disease may be another sign of FH. If they are older, they might have symptoms of cardiovascular disease, which develops as a result of atherosclerosis. If so, they may experience angina pectoris – a crushing pain behind the breastbone, sometimes radiating to the arm or neck, associated with physical exertion or cold. If these symptoms become severe and sustained it may be a sign of a heart attack.
How Is Familial Hypercholesterolemia Diagnosed?
FH diagnosis requires a blood sample taken from the patient after a 10-hour fast, during which only water is permitted. The blood test determines the level of total cholesterol, as well as LDL, HDL and triglycerides. If LDL-cholesterol is very high level, it suggests the presence of inherited hypercholesterolemia. If both LDL-cholesterol and triglycerides are very high, the patient may have familial combined hyperlipidemia, another genetic condition.
In addition, the doctor usually conducts a physical examination of the patient. The heart and large blood vessels are checked, the pulse and blood pressure are measured, and the patient may be asked to do an exercise stress test. These tests enable the doctor to estimate the extent of cardiovascular disease (if any).
What Is The Treatment For Familial Hypercholesterolemia?
FH is treated with cholesterol-lowering medications combined with a program designed to improve diet and exercise. Meds are always necessary since it is not possible to normalise high cholesterol levels caused by FH through lifestyle changes alone. Doctors typically rely on statins as their first choice of cholesterol medicine. These reduce LDL cholesterol production in the liver, which commonly reduces serum LDL levels by as much as 50 percent. Other cholesterol-lowering meds include: anion exchange resins (bile acid sequestrants) to increase LDL secretion, and fibrates to prevent LDL uptake in the digestive tract intestine. Combined treatment with statins, anion exchange resins and diet typically lowers total serum cholesterol by 30 to 40 per cent and LDL-cholesterol even more. Ideally, treatment for inherited hypercholesterolemia should be given by a specialist lipid clinic.
What Are The Health Risks Of Familial Hypercholesterolemia?
The development and consequences of FH varies from patient to patient, although typically it follows a similar pattern in a particular family. Patients with FH have a significantly higher risk of a fatal heart attack before the age of 40 than the general population. Studies indicate that 1 in 2 men with FH and 4 out of 10 women with FH have had a blood clot in their coronary arteries before the age of 60. Approximately 1 in 3 patients with FH show no symptoms until they experience a fatal heart attack.