VWF and Thrombocytopenia: Abnormalities of GPIb-IX-V expression or an abnormal interaction between newly synthesized VWF with GPIb-IX-V in the megakaryocytes of a family with VWD2B caused by VWF R1308P lead to impaired megakaryocytopoiesis and thrombocytopenia (Nurden et al. 2006, 2010).