[Definition of thrombophilia]

Thrombophilia is characterized by clinical tendency to thrombosis or molecular abnomalities of hemostasis that predisposes to thromboembolic disease. Hereditary thrombophilia may be due to antithrombin deficiency, or protein C or protein S deficiency. More recently, other molecular abnormalities have been described: activated protein C resistance due to factor V Leiden, G 20210 A polymorphism on the prothrombin gene, increased factor VIII plasma levels or hyperhomocysteinemia. Acquired thrombophilia is frequently associated with the antiphospholipid syndrome characterized by thrombosis and presence of lupus anticoagulant or phospholipid-binding antibodies. In some cases, no molecular abnormality is found despite recurrent thrombosis observed in patient and his/her family. This situation can be considered as clinical thrombophilia.