F5 and thrombophilia: Thrombophilia is defined as a tendency towards thrombosis resulting from hereditary alterations (deficiency of proteins C, S and antithrombin; factor V Leiden − FVL − mutation; and protrombin gene mutation) or acquired from coagulation (antiphospholipid syndrome) that lead to a state of pro-thrombosis, which predisposes people to present with venous or arterial thrombosis.