The revised classification of von Willebrand disease including the previously masqueraded female hemophilia A (type 2N).

The revised classification of von Willebrand disease was proposed by the working committee (Chairperson: J.E. Sadler) and approved by the Scientific and Standardization Committee/the International Society on Thrombosis and Hemostasis in 1993. It consists of three major types; type 1 with decreased level of normal von Willebrand factor (VWF) and type 3 with complete deficiency of VWF as quantitative abnormality, and type 2 with qualitative anomaly of VWF subcategorized into 2A, 2B, 2M and 2N, respectively, depending on the functional abnormalities (decrease of GPIb binding with defect of VWF large multimers, increase of GPIb binding, decrease of GPIb binding with VWF large multimers, decrease of FVIII binding). This classification is frequently quoted in the USA and Europe. We introduce this classification and review again the structural abnormalities of VWF, including the previously masqueraded female hemophilia A (type 2N).