F5 and thrombophilia: Causes of hereditary thrombophilia include factor V Leiden mutation (activated protein C [PC] resistance); prothrombin 20210A mutation; PC, protein S (PS), and antithrombin III (AT III) deficiencies; lupus anticoagulant; anticardiolipin antibodies; methylenetetrahydrofolate (MTHFR) gene mutation; and hyperhomocysteinemia[1].