A second mutation in the methylenetetrahydrofolate reductase gene and the risk of venous thrombotic disease

We assessed the effect of a recently described mutation in the MTHFR gene ( 1298 A --> C) on the risk of deep venous thrombosis (DVT) by determining it s prevalence in 190 patients with verified DVT and in age-, race- and gende r-matched controls. MTHFR 1298 A --> C was found in 42.1% of patients and i n 41.1% of controls. The OR for venous thrombosis was 1.07 (95% CI 0.70-1.6 5) for heterozygotes and 0.83 (95% CI 0.33-2.08) for homozygotes. The OR fo r the factor V Leiden (FVL) mutation was 3.40 (95% CI 1.22-9.48), for FII 2 0210 G --> A was 5.22 (95% CI 1.12-24.2) and for MTHFR 677 C --> T, 1.24 (9 5% CI 0.82-1.87). No significant increased risk for venous thrombosis was f ound when MTHFR 1298 A --> C was coinherited with FVL (OR 2.85, 95% CI 0.88 -9.23), FIT 20210 G --> A (OR 7.19, 95% CT 0.87-59.4) or MTHFR 677 C --> T (OR 1.44, 95% CT 0.71-2.92). These data do not support a critical role of M THFR 1298 A --> C in the predisposition to DVT.