title: Distinguishing between type 2B and pseudo-von Willebrand disease and its clinical importance.
abstract: Pseudo-von Willebrand disease (p-VWD) and type 2B von Willebrand disease (VWD) have similar phenotypic parameters and clinical symptoms, but different aetiologies. Fourteen individuals from five families with a historical diagnosis of type 2B VWD but with no mutation in the von Willebrand factor gene were re-investigated for the possibility of p-VWD, using platelet aggregation in the presence of cryoprecipitate. p-VWD was confirmed by targeted DNA sequencing of the glycoprotein Ibalpha gene, identifying a heterozygous Glycine 233 Valine substitution. This study suggests that p-VWD may be under diagnosed, and that platelet aggregation in the presence of cryoprecipitate is useful in differentiating this disorder from type 2B VWD.
authors.affiliation: Department of Haematology, The Birmingham Children's Hospital NHS Trust, Birmingham, UK. said.enayat@bch.nhs.uk
authors.forename: Mohammad S
authors.initials: MS
authors.lastname: Enayat
authors.forename: Andrea M
authors.initials: AM
authors.lastname: Guilliatt
authors.forename: William
authors.initials: W
authors.lastname: Lester
authors.forename: Jonathan T
authors.initials: JT
authors.lastname: Wilde
authors.forename: Michael D
authors.initials: MD
authors.lastname: Williams
authors.forename: Frank G H
authors.initials: FG
authors.lastname: Hill
mesh_terms: D004252:DNA Mutational Analysis / Q000379:methods; D003937:Diagnosis, Differential; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D009154:Mutation; D010641:Phenotype; D010974:Platelet Aggregation; D010976:Platelet Count; D019038:Platelet Glycoprotein GPIb-IX Complex / Q000235:genetics; D014842:von Willebrand Diseases / Q000097:blood / Q000175:diagnosis* / Q000235:genetics
chemical_list: D019038:Platelet Glycoprotein GPIb-IX Complex