Furthermore, according to the American Society of Hematology and the International Society on Thrombosis and Haemostasis, a decrease in VWF:RCo, VWF:CB, and/or VWF:Ag are essential criteria for the diagnosis of hereditary VWD [7], whereas they are not included in the diagnosis of AVWS. This evidence concerns the gene VWF and von Willebrand disease (hereditary or acquired).