Rare bleeding disorders (RBDs), representing 3–5% of all inherited coagulation factor deficiencies, include the inherited deficiencies

of fibrinogen, factor (F)II, FV, FV+FVIII, FVII, FX, FXI and FXIII, generally transmitted to both sexes in an autosomal recessive manner [1]. The prevalence of homozygous or double homozygous forms in the general population varies from 1 in 500 000 for FVII deficiency to 1 in 2000 000 for FII and FXIII deficiencies [1]. RBDs are characterized by a wide variety of find more symptoms ranging from mild to severe, which can vary significantly from one disorder to another and from one patient to another, even when suffering from the same type of disorder. The clinical heterogeneity of RBDs combined with their rarity is a significant barrier to enhancing deeper knowledge about them. Diagnosis, classification and adequate treatment of these disorders has been hampered by their variable clinical presentation, the difficulty in recognizing

affected patients, challenges in collecting longitudinal clinical data and limits of laboratory assays. Therefore, a tool that could help us to diagnose and to predict the clinical severity pattern for each patient would be important. In the first part of this article, Dr P. James from Queen’s University, Kingston, Canada, MG-132 order will discuss the application of different bleeding assessment tools in RBDs. In the second part of this article, Professor O. Salomon, from the University of Tel Aviv, Israel, will focus on the treatment of patients with FXI deficiency. Unlike other coagulation factor deficiencies, FXI deficiency rarely presents spontaneous bleeding; rather, bleeding usually occurs following surgery or trauma. This feature, together with the lack of correlation between clinical severity and plasma FXI coagulant levels, and the risk of thrombosis associated with replacement therapy, makes management of these patients difficult. Finally, Dr D. Mikovic, from the Blood Transfusion

Institute of Serbia, Acetophenone will argue the importance of finding a correlation between coagulant activity and clinical severity in RBDs to determine the haemostatic level of each single factor required to prevent haemorrhage. A special mention will be made of the importance of standardization of available coagulant assays. Paula James, Department of Medicine, Queen’s University, Kingston, Canada. The accurate assessment of haemorrhagic symptoms is a key component in the diagnosis of bleeding disorders, including RBDs. However, the evaluation of bleeding symptoms is a well-recognized challenge for both patients and physicians, because the reporting and interpretation of bleeding symptoms is subjective.