The End of a Long Debate: Methylenetetrahydrofolate Reductase Gene Polymorphisms do not Increase Thrombosis Risk.

We read the article by Ozturk et al. [1], in which they reported the frequency of some thrombophilic mutations in eastern Turkey. The authors have defined single nucleotide gene variations of factor V Leiden, prothrombin G20210A, and methylenetetrahydrofolate reductase (MTHFR) C677T as thrombophilic mutations. However, as current scientific data do not support an increased risk of thrombosis in the presence of MTHFR gene polymorphisms, MTHFR C677T is not presently regarded as a thrombophilic mutation. In a recent metaanalysis involving over 11,000 cases and 21,000 controls, a significant association with venous thromboembolism was not observed for homozygous MTHFR C677T, whereas carriers of either heterozygous factor V Leiden or prothrombin G20210A, double heterozygotes and homozygous factor V Leiden or prothrombin G20210A exhibited an increased risk of thrombosis [2].