ABSTRACT
INTRODUCTION Hereditary deficiency of each of the 12 coagulation factors has been reported. von Willebrand’s disease, haemophilia A (factor VIII deficiency) and haemophilia B (factor IX deficiency) account for 82.6% of all patients registered on the UK Haemophilia Centre Doctors’ Organisation registry in 1997, and factor XI deficiency account for another 4.9%. Other rarer coagulation defects (deficiencies of fibrinogen, prothrombin, factor V, factor VII, factor X, factor XII and factor XIII, combined factor deficiency and platelet defects) account for the remaining 12.5%. Factor XI deficiency is the most common genetic disorder among Ashkenazi Jews, and the frequency of heterozygous status is reported to be 8% in this population.1
