Factor V G1691A, prothrombin G20210A, and methylenetetrahydrofolate reductase [MTHFR] C677T gene polymorphism in angiographically documented coronary artery disease.

BACKGROUND: Single point mutations in the genes coding for factor V [G1691A; Leiden], prothrombin [PRT; G20210A], and methylenetetrahydrofolate reductase [MTHFR, C677T] were shown to be major inherited predisposing factors for venous thromboembolism. However, their contribution in the development of coronary artery disease [CAD] remains controversial. The aim of the study was to examine the association of these mutations in CAD.

METHODS: A total of 96 patients with angiographically-demonstrated CAD [mean age 55.3 +/- 11.3], and 404 healthy subjects [mean age 50.7 +/- 8.9] were recruited into the study. Fasting plasma homocysteine was determined by HPLC, and genotype analysis was assessed by PCR-RFLP.

RESULTS: The carrier frequency of factor V-Leiden (14.6% vs. 15.1%, p = 0.617) and PRT G20210A (3.1% vs. 3.0%; p = 0.936) were similar between patients and controls, respectively. In contrast, the frequency of the MTHFR variant C677T was 71.9% among patients compared with 45.5% in controls (p < 0.001), of which the T/T genotype was significantly higher among patients (31.3%) than controls (4.5%; p < 0.001). Significantly higher homocysteine levels were seen among T/T genotype in both groups compared to non-T/T carriers (p < 0.05), and among patients compared with controls (18.47 +/- 3.73 micromol/L vs. 16.28 +/- 4.16 micromol/L). In addition, the coexistence of MTHFR C677T with FV-Leiden was seen in 10.4% of CAD patients compared 6.9% of controls (p = 0.001).

CONCLUSION: While results from this study clearly demonstrate a strong association of hyperhomocysteinemia and homozygosity of the MTHFR C677T, but not FV-Leiden or PRT G20210A, mutations with confirmed CAD, they also suggest a potential role for factor V-Leiden in MTHFR C677T carriers.