Molecular evaluation of exon ۲۸ von willebrand factor gene in the diagnosis of type ۲B VWD in patients referred to the Iranian BloodTransfusion Organization

Backgrounds: Von willebrand disease (VWD) is most common inherited bleeding disorder witha prevalence of ۱% in the global population. Type ۲VWD includes four types (۲A, ۲B, ۲M, ۲N).Type ۲B VWD is rare subtype consisting about ۵% of all VWD. Laboratory diagnosis of type ۲BVWD is challenging and needs a complex phenotype and genotype analysis.Materials and Methods: In a ۳ years period of time all cases referred to the IBTO referencecoagulation lab, cases who referred for VWD and showing a minimum criteria as response tolow-dose RIPA test selected for the study. VWF: Rco, VWF: Ag, FVIII: C and RIPA tests wereperformed. Cases suspected for type ۲B VWD were evaluate for exon ۲۸ molecular testing.Results: ۷ case suspects for type ۲B/platelet type VWD found. Our results were Age (median:۱۸y, range: ۳–۵۶y), Sex (men: ۶, female: ۱), VWF: Ag (median: ۵۷, range: ۴۴–۱۱۷) VWF:Rco (median: ۲۸, range: ۲–۹۱) FVIII:C (median: ۶۶, range: ۲-۱۴۸) VWF: Rco / Ag(median: ۰.۶, range: ۰.۰۴–۰.۷۷). We were detected the variants c.۳۹۴۶G>A p. V۱۳۱۶M;c.۳۷۳۵G>A p. V۱۲۴۵V; c.۳۷۸۹G>A p. S۱۲۶۳S; c.۳۷۹۷C>T p. P۱۲۶۶L. Molecular testing ofexon ۲۸ was for ۳ cases as type۲B VWD. The other ۴ cases (member of a family) not approvedfor type ۲B by molecular testing, however platelet type VWD should be excluded in this family.Conclusion: A panel of testing included molecular analysis to needed for confirmation orexclusion of type ۲B VWD.

کلیدواژه ها:

Von willebrand disease ، Type ۲B von willebrand disease ، Molecular analysis