The development of registries through international collaboration has facilitated better understanding of the rare bleeding disorders. Such work has shown that rare bleeding disorders are heterogeneous and need to be studied singularly, and that heterozygous patients may bleed. There is a need to understand the minimum plasma coagulant activity level to prevent spontaneous bleeding. Moreover, due to the low prevalence of rare bleeding disorders, the management of this patient population remains a challenge. Data collection on clinical history, efficacy and side effects of treatment needs to be harmonised.
1. European Commission. Useful information on rare diseases from an EU perspective. Available at http://ec.europa.eu/health/ph_information/documents/ev20040705_rd05_en.pdf
2. World Federation of Hemophilia. Annual Global Survey, 2013. Available at http://www1.wfh.org/publications/files/pdf-1591.pdf
3. Peyvandi F, Palla R, Menegatti M, Mannucci PM. Introduction. Rare bleeding disorders: general aspects of clinical features, diagnosis, and management. Semin Thromb Hemost 2009; 35: 349-55.
4. Peyvandi F, Palla R, Menegatti M, et al. Coagulation factor activity and clinical bleeding severity in rare bleeding disorders: results from the European Network of Rare Bleeding Disorders. J Thromb Haemost 2012; 10(4): 615-21. doi:
7. McIntosh J, Lenting PJ, Rosales C, et al. Therapeutic levels of FVIII following a single peripheral vein administration of rAAV vector encoding a novel human factor VIII variant. Blood 2013; 121(17): 3335-44. doi: