Hereditary von Willebrand disease (VWD) is a hereditary bleeding disorder caused by a genetic anomaly leading to quantitative, structural or functional abnormalities of the Willebrand factor (von Willebrand factor; VWF). Two major groups of VWF deficiency have been defined: quantitative and partial (type 1) or total (type 3), and qualitative (type 2) with several subtypes (2A, 2B, 2M, 2N).