The Genetic Background of Thrombosis - The Distributions of Factor V Leiden, Prothrombin G20210A, and MTHFR C677T Polymorphisms

Background. Polymorphisms of factor V ( Leiden) (G1691A) and the gene for prothrombin (G20210A) are the main single-nucleotide polymorphisms ( SNPs) connected with thrombotic disease. The polymorphism C677T in MTHFR gene may be implicated in the development of hyperhomocysteinemia, what is also a risk factor of thrombosis. The genetic diagnostics of these mutations is a valuable complement to the clinical diagnosis. It permits establishing the causes of disease and planning therapy. Objectives. To evaluate associations of the polymorphisms with thrombosis, the distributions of the three major SNPs in factor V, prothrombin, and MTHFR genes in patients with diagnosed venous thromboembolic disease were investigated. Material and Methods. DNA was isolated from the patients' whole blood. A very sensitive method, ASO-PCR, to detect point mutations in the selected genes was used. The PCR products were analyzed by agarose gel electrophoresis with ethidium bromide. Results. Among 117 Polish patients, 99 mutation carriers were found: 26 of factor V Leiden, 13 of prothrombin G20210A, and 60 of MTHFR C677T. The frequencies of the obtained genotypes were compared with those of a healthy Caucasian population. Positive correlation of two SNPs ( factor V Leiden and prothrombin G20210A) was found in study group; however, the MTHFR C677T polymorphism was not directly linked with thrombotic incidence. Conclusions. These data indicate that only two of the SNPs, FVL and prothrombin G20210A, are related to disease phenotype (Adv Clin Exp Med 2010, 19, 1, 51-55).