Is cholesterol genetic

Familial hypercholesterolemia

Familial hypercholesterolemia (FH) is one of the most common genetic diseases and is characterized by an increased concentration of LDL cholesterol in the blood.

High LDL cholesterol (the "bad" cholesterol) is the number one risk factor for atherosclerosis and cardiovascular disease. These are the leading cause of death in industrialized countries such as Austria - but can be avoided by normalizing the LDL level through lifestyle adjustments or drug therapies.

What types of familial hypercholesterolemia are there?

Familial hypercholesterolemia can have different genetic causes: an LDL receptor defect, an Apo B defect or a PCSK-9 defect.

In the case of an LDL receptor defect, the FH results from a single mutation - a mutation on chromosome 9. The LDL receptors are usually defective or inactive. LDL receptors are mechanisms that help cells absorb and metabolize LDL cholesterol. If these receptors are defective, more LDL particles can get into the blood and gradually accumulate on the vessel walls. Depending on the mutation and how it is inherited, atherosclerosis and cardiovascular disease can progress at different rates. With the frequent heterozygous form (1: 200) this happens rather slowly, with the very rare homozygous form (1: 1 million), for example, vascular constrictions can develop in childhood.

In addition to the LDL receptors, an important intermediate step can also be disturbed in its function: LDL is first bound to the LDL receptor via the apolipoprotein B-100 (Apo B). If this mutates at a certain point, the LDL receptor can no longer bind the LDL cholesterol to the cell and accordingly cannot burn it. This form is called familial defective apolipoprotein B 100 (FDB).

Another cause can be found in the mechanism of the LDL transporter (PCSK-9 defect).

What are the symptoms of familial hypercholesterolemia?

Like any hypercholesterolemia, the UAS is treacherous: it is invisible and not noticeable. Symptoms only become noticeable when the resulting atherosclerosis has progressed so far and one or more vessels are severely narrowed or completely closed. Usually coronary heart disease or a heart attack is the first symptom.

It is very important to take a family history: If there are people in the family who have suffered a heart attack before the age of 60 or who have hypercholesterolemia, the suspicion of FH is high.

How is familial hypercholesterolemia diagnosed?

After family history, the first diagnostic step is to determine total, LDL, and HDL cholesterol in the blood. The patient does not necessarily have to be sober. If the LDL increase is> 190 in adults or> 130 in children, it is very likely that FH is present. A comprehensive genetic examination (gene sequencing) can confirm the diagnosis and identify other family members who did not know about the disease.

If hypercholesterolemia is present, the doctor must determine whether other primary diseases (e.g. diabetes, hypothyroidism) are the cause. In addition, an arteriosclerosis risk profile is drawn up. If a family disorder is suspected, gene sequencing including family screening can provide information.

How is familial hypercholesterolemia treated?

Since an increased LDL and total cholesterol level increases the risk of atherosclerosis and secondary diseases of the cardiovascular system, it is necessary to bring the blood values ​​into a harmless range. Basically, if you have LDL cholesterol levels below 70 mg / dl all your life and have no other risk factors, you will rarely develop arteriosclerosis. The value to which the LDL level of the FH patient should be lowered is individual and depends on certain risk factors - however, it ranges between <70 and <130 mg / dl.

In order to achieve this therapy goal, the following steps are necessary:

  • Improvement in lifestyle and eating habits: LDL lowering of around 10-15% is possible
  • Reduction of risk factors: Immediate smoking cessation, minimization of alcohol consumption, reduction of obesity, increased exercise and sport, treatment of high blood pressure and diabetes
  • Nutritional therapy (with check-ups after 4 and 8 weeks): Limiting the daily intake of animal fats is a basic principle. A diet consisting of high-fiber food, complex carbohydrates, proteins and lots of nutritious fruits and vegetables is recommended.
  • Drug therapies: The first choice are the so-called CSE inhibitors, also called statins: They lower the LDL cholesterol level and are successfully used in all diseases associated with atherosclerosis. A smaller dose is usually started, the blood values ​​are then checked again after about 3 weeks. If the LDL level is still too high, the dose can be increased. This can be repeated until the patient's cholesterol level is optimally adjusted. If the statins are not sufficient, anion exchange resins or bile acid binders can also be used, which stimulate the LDL receptor activity in the liver. Furthermore, cholesterol absorption inhibitors are also used in combination or on their own. The so-called PCSK-9 inhibitors are new: They are injected into the muscle (e.g. upper arm) every 2 - 4 weeks and can lower the LDL values ​​by up to 50%. According to experts, these drugs have ushered in a new era of drug-based FH therapy.
  • In the case of particularly severe FH, the LDL cholesterol can also be filtered directly from the blood if the LDL level cannot be reduced sufficiently with medication. This is done outside of the body via what is known as LDL apheresis. Depending on the method, the LDL cholesterol is eliminated from the whole blood or from the blood plasma. This is repeated about once a week and shows good results.

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Familial hypercholesterolemia: summary

Familial hypercholesterolemia is one of the most common congenital metabolic diseases. The most common form (heterozygous FH) affects one in 200 people. Most affected patients are unaware of their illness and are therefore not treated. The family history is essential here: frequent infarcts, strokes, etc. in the family require an exact examination of the entire family, including the children.

Treatment - even in childhood - has been proven to be successful, but must be carried out consistently. It is certain that this will prevent heart attacks from occurring.

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Authors:
Katrin Derler, BA
Medical review:
Prim. Univ.Prof. Dr. Kurt Widhalm

Status of medical information:

ICD-10: E78.0