Antithrombin Deficiency

As its name suggests, the protein Antithrombin is not a clotting factor but an inhibitor of thrombin. Thrombin is the potent active enzyme that is the end result of the cascade of clotting factor reactions and which acts on plasma fibrinogen to form a fibrin clot. Congenital Antithrombin deficiency is not uncommon, with roughly 1 in 5000 of the population affected. The condition is not sex-linked so both males and females may be affected. Although many affected individuals are, fortunately, asymptomatic, some who have a deficiency of Antithrombin in their blood, or whose Antithrombin is defective in some way, are at risk of thrombosis, particularly deep vein thrombosis, at a young age. Affected women are at particular risk during pregnancy. The most common treatment is to use oral anticoagulants. Heparin may be used during an acute thrombotic event, whereas warfarin (coumarin) may be prescribed for affected, symptomatic individuals on a life-long basis. Replacement therapy with Antithrombin concentrates are used in particular situations: when heparin or warfarin are contra-indicated (for example during pregnancy), or for high-risk situations when heparin is ineffective or individuals are critically ill.

For further information, please contact your GP.