Type 2B von Willebrand's disease in thirteen individuals from five unrelated Australian families: Phenotype and genotype correlations

Type 2B von Willebrand's disease (VWD) is due to a qualitative defect in vo n Willebrand factor (VWF) in which there is an increased affinity for the p latelet glycoprotein Ib-IX-V receptor complex. Spontaneous binding of type 2B VWF to platelets and subsequent clearance from the plasma is thought to account for the characteristic phenotype of type 2B VWD. These gain-of-func tion mutations are due to single amino substitutions that are clustered wit hin the functionally important Al domain of VWF. We describe 13 individuals from five unrelated families in Australia with type 2B VWD, report their p henotypic abnormalities, and delineate their causative mutations. We confir m that the mutation Arg543Trp is also particularly common among families wi th type 28 VWD in Australia. Am. J. Hematol. 63:197-199, 2000. (C) 2000 Wil ey-Liss, Inc.