Distinguishing between type 2B and pseudo-von Willebrand disease and its clinical importance

SummaryPseudo-von Willebrand disease (p-VWD) and type 2B von Willebranddisease (VWD) have similar phenotypic parameters and clinical symptoms,but different aetiologies. Fourteen individuals from five families with ahistorical diagnosis of type 2B VWD but with no mutation in the vonWillebrand factor gene were re-investigated for the possibility of p-VWD,using platelet aggregation in the presence of cryoprecipitate. p-VWD wasconfirmed by targeted DNA sequencing of the glycoprotein Iba gene,identifying a heterozygous Glycine 233 Valine substitution. This studysuggests that p-VWD may be under diagnosed, and that platelet aggregationin the presence of cryoprecipitate is useful in differentiating this disorderfrom type 2B VWD.Keywords: pseudo-von Willebrand disease, type 2B von Willebrand disease,platelet aggregation with cryoprecipitate, mutation, GPIba gene. short report a 2006 The Authorsdoi:10.1111/j.1365-2141.2006.06078.x Journal Compilation a 2006 Blackwell Publishing Ltd, British Journal of Haematology, 133, 664–666