The risk of recurrent venous thromboembolism in patients with an Arg506→Gln mutation in the gene for factor V (factor V Leiden). - Simioni, P; Prandoni, P; Lensing, AW; Scudeller, A; Sardella, C; Prins, MH; Villalta, S; Dazzi, F; Girolami, A (N Engl J Med, 1997)