High Levels of Factor VIII and Venous Thrombosis

The first families with a tendency to venous thrombosis were reported in the early 1900s. In 1965, Egeberg reported a family with thrombophilia and an identified hereditary defect (antithrombin deficiency). In the early 1980s, deficiencies of other natural anticoagulants – protein C and protein S – were shown to be associated with venous thrombosis in families with familial thrombophilia. Recently, several other blood abnormalities have been described that increase the risk of thrombosis: resistance to activated protein C, usually the result of a mutation in factor V (factor V 1691A or factor V Leiden), a mutation in the prothrombin gene (PT20210A), and high levels of clotting factor VIII (5–8).