A common mutation in the methylenetetrahydrofolate reductase gene (C677T) increases the risk for deep-vein thrombosis in patients with mutant Factor V (Factor V:Q506) - Cattaneo, M; Tsai, MY; Bucciarelli, P; Taioli, E; Zighetti, ML; Bignell, M; Mannucci, PM (Arterioscler Thromb Vasc Biol, 1997)