Current therapy for rare factor deficiencies.

Haemophilia A and B and von Willebrand disease account for 80-85% of all inherited bleeding disorders. The other 15% are represented by deficiencies of fibrinogen, prothrombin, or factors V, VII, X, XI, or XIII. In addition, acquired factor deficiencies are seen in a variety of conditions ranging from malignancies to autoimmune disorders. The spectrum of symptoms in these conditions varies from severe and life-threatening haemorrhage to a mild bleeding diathesis. The diagnosis depends on demonstration of decreased activity of one of the clotting factors. Due to the rarity of each of the individual factor deficiencies, purified factor concentrates are not as readily available as they are for haemophilia A and B. Treatment of rare clotting factor deficiencies consists of the most purified blood product available that contains the missing factor. Depending on which factor is deficient, either purified concentrates, prothrombin complex concentrates, cryoprecipitate, or fresh frozen plasma can be used. In addition, recombinant factor VIIa is available for treating factor VII deficient patients.