Rare bleeding disorders: a narrative review of epidemiology, molecular and clinical presentations, diagnosis and treatment

Rare bleeding disorders (RBDs) are a heterogeneous group of disorders including different types of coagulation factor deficiencies. The disorders are inherited in an autosomal recessive manner with different frequencies varying from 1:500000 to 1:2000000. Patients affected with RBDs are presented with a wide spectrum of clinical manifestations ranging from mild to life threatening bleeding diathesis. These disorders are usually present in regions with high rate of parental consanguinity. Despite the rare incidence of RBDs, it is necessary for physicians to be aware of these disorders. Here we aim to have a comprehensive review on general features and also the recent advances in understanding of RBDs. MEDLINE and Web of Science databases searched for English sources from 1990 to 2014, using the following keywords: rare bleeding disorder, rare inherited disorder, factor deficiency, structure, function, epidemiology, manifestations, laboratory analysis, diagnosis, mutation, treatment, management and also all the factor deficiencies which are considered as RBD. Knowledge towards RBDs is increasing, however, most of published data are limited to small group of populations or case reports. Therefore, there are still several questions on these rare disorders which need to be clarified through large prospective studies.