A common mutation in the methylene tetrahydrofolate reductase gene (C 677T) increases the risk for deep-vein thrombosis in patients with mutant factor V (factor V: Q506) - Cattaneo, M; Tsai, MY; Bucciarelli, P; Taioli, E; Zighelti, ML; Bignell, M; Mannucci, PM (Arterioscler Thromb Vasc Biol, 1997)