Analysis of factor V Leiden and prothrombin mutations in patients with suspected thrombophilia in São Paulo state-Brazil

Abstract

Introduction: Prothrombin (factor II) is a thrombin precursor, which induces fibrin formation. A mutation in the prothrombin gene (G20210A) has been described, which is directly associated with high prothrombin levels, hence thrombophilia. G1691A mutation in the factor V Leiden (FVL) gene occurs on exon 10, one of the main cleavage sites for protein C activation, resulting in protein alteration. Objective: To identify and estimate the genotype frequency of the three possible genotypes and the frequency of the two existing alleles in the FVL and prothrombin genes in patients with suspected thrombophilia in the state of Sao Paulo. This study may provide more literature and reference data on the incidence of prothrombin genotypes among individuals in Brazil. Material and methods: Analysis of point mutation by real time polymerase chain reaction (RT-PCR). Results: We obtained a total of 100 individuals, from which 94% had the homozygous G genotype. Only 6% had heterozygous genotype and there was no individual with the homozygous genotype A for FVL gene. As to the prothrombin gene, the frequency was 97% for homozygous G genotype and 3% for the heterozygous genotype. There was no patient with the homozygous A genotype. Conclusion: This study demonstrated that the genotype identification of these genes is advisable for patients with suspected thrombophilia in this region.

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“…Prothrombin is a blood protein synthesized in the liver in the presence of vitamin K. It is a precursor of thrombin, which activates fibrin formation at the end of the coagulation cascade [14]. The G20210A variation in the prothrombin Factor II gene is the most common genetic defect found in coagulopathies after Factor V Leiden and is associated with an increase in prothrombin levels, leading to a threefold increase in the risk of venous thrombosis [15].…”