Prophylaxis in rare coagulation disorders -- factor X deficiency.

Factor X (FX) is a vitamin K-dependent protease that plays a central role in the blood coagulation cascade. Deficiency of FX is one of the rarest congenital coagulation disorders, resulting in a variable clinical phenotype. The molecular basis for FX deficiency is characterised by a large number of gene mutations and polymorphisms. The Greifswald Registry of FX deficiency was started in 1998 and aims to investigate the relationship between genetic mutations and the clinical severity of the disease. To date, 34 of 102 patients have been treated for severe bleeding episodes or for surgical procedures. Only seven patients, six of whom are children, receive regular prophylaxis with Factor IX (FIX) concentrate (FIX HS, ZLB Behring; also containing approximately 800IU FX). In all cases, the bleeding episodes are well controlled without any serious treatment-related complications.