European registry of rare bleeding disorders

Rare bleeding disorders (RBDs) are autosomal recessive diseases including the deficiencies of coagulation factors such as fibrinogen, factor (F)II, FV, FV+FVIII, FVII, FX, FXI and FXIII. Their prevalence in the general population varies from 1 in 500.000 for FVII and FXI deficiency up to 1 in 2 million for FXIII deficiency. As a consequence of their rarity, the type and severity of bleeding symptoms, and the management of bleeding episodes, are not well established. A definition of clinical severity in RBDs is lacking and a large heterogeneity of clinical manifestations is observed in different RBDs. We tried to describe the general features of RBDs based on data from previously reported literature and on the results of three years of collaboration between 11 European treatment centers in the frame of a project funded in the European Union, entitled “Establishment of a European Network of Rare Bleeding Disorders: EN-RBD.” Our results might help to provide novel information on the clinical severity of the different RBDs and on its correlation to the laboratory phenotype