The risk of initial venous or arterial thromboembolism depends on the type of thrombophilia–heterozygous factor V Leiden, prothrombin mutations increase the risk of venous thromboembolism up to four-fold (the risk being higher in a homozygous or compound state), antithrombin deficiency up to 16-fold, protein C and S deficiency up to 8-fold and 7-fold respectively, whereas the presence of antiphospholipid antibodies are associated with both arterial (primarily) and venous thrombosis risk increase [10]. This evidence concerns the gene F2 and thrombophilia.