The results were controversial Four studies presented significant association between factor V Leiden mutation (or activated protein C resistance) and vascular complications in BD patients (Gul et al. [2], and Gurgey et al. [14] from Turkey, Mammo et al. [15] from Saudi Arabia, Navarro et al. [16] from Spain), while other studies reported that there was no significant association ( Toydemir et al. [17] from Turkey, Verity et al. [18] from Jordan, Silingardi et al. [19] from Italy). This evidence concerns the gene F5 and Behcet disease.