Apolipoprotein E (ApoE), or “managers’ gene”, the gene responsible for common diseases that are common among managers is located on chromosome 19. ApoE encodes one of the proteins in the plasma.
ApoE has three major forms, or alleles, in humans: ε2, ε3 and ε4. (An allele is one member of a pair or series of different forms of a gene that encodes varieties of a trait.) As chromosomes form pairs, each gene of the human genome (i.e. the sum total of all genes in the human cell) has two alleles, so the three ApoE alleles combine into a total of six variations (ε2/ε2, ε2/ε3, ε2/ε4 ε3/ε3, ε3/ε4, ε4/ε4), which cause an increased susceptibility to different diseases:
|ε2/ε2||It strongly increases susceptibility to type III hyperlipoprotenemia (HLP III) but protects against Alzheimer’s disease. It is associated with pathological glucose tolerance. Diet is effective in offsetting the negative effect.|
|ε3/ε3||It does not increase susceptibility to cardiovascular diseases and Alzheimer’s disease (AD), and protects from HLP III.|
|ε4/ε4||It strongly increases susceptibility to high serum cholesterol, coronary disease and Alzheimer’s disease, with an even higher risk of AD in women. Environmental risk factors are also necessary for these diseases to develop.|
|ε2/ε3||It slightly increases susceptibility to HLP III and has the lowest risk of Alzheimer’s disease.|
|ε2/ε4||It slightly increases susceptibility to HLP III and increases the risk of AD particularly in women.|
|ε3/ε4||It does not increase susceptibility to HLP III but increases the risk of coronary disease and AD.|
Testing for susceptibility to thrombosis (factor V Leiden mutation, MTHFR C677T, prothrombin G20210A)
Deep venous thrombosis and its complications are among the frequent afflictions of the Hungarian population. Blood coagulation is the result of the complex interplay of different proteins (coagulation factor). If this delicate balance is upset because of the defect or absence of one of the regulators, depending on the function of the protein hemophilia or clotting (thrombosis, thromboembolism) can develop. Generally there is some genetic defect in the background. About 30-40% of thromboembolism is caused by hereditary factors.
Thrombosis has a number of risk factors:
- Hereditary genetic abnormalities
- Prolonged bed rest
- Major surgery
- Heart failure (slow circulation, ventricular fibrillation)
- Kidney disease (nephrosis syndrome)
- Pregnancy and childbirth
- Oral contraceptives
Susceptibility to thrombosis increases if several risk factors prevail simultaneously. Genetic testing for thrombosis or thrombophilia contributes to the diagnosis, and helps to identify high-risk groups who may need special monitoring, prophylactic anti-clotting medication and a change in lifestyle.