The molecular biology of von Willebrand disease

von Willebrand disease (VWD) is a common autosomally inherited bleeding dis order associated with mucosal or trauma-related bleeding in affected indivi duals. VWD results from either a quantitative or qualitative deficiency of von Willebrand factor (VWF) - a glycoprotein with essential roles in primar y haemostasis and as a carrier of coagulation factor VIII (FVIII) in the ci rculation. In recent years the identification of mutations in the VWF gene in patients with VWD has improved our understanding of the structure and fu nction of the VWF protein, and has illustrated the importance of specific r egions of VWF for its interaction with other components of the vasculature. The underlying genetic lesions and associated molecular pathology have bee n identified in many cases of type 2A, type 2B, type 2M, type 2N and type 3 VWD. However in the most common variant, type 1 VWD, the causative molecul ar defect is unknown in the large majority of cases. In the absence of an u nderstanding of the molecular pathology underlying type 1 VWD, precise diag nosis and classification of this common disorder remains problematic.