title: Identification of von Willebrand disease type 2N (Normandy) in Australia: a cross-laboratory investigation using different methods.
abstract: We report on a cross-laboratory study of type 2N von Willebrand disease (vWD). We tested 101 selected plasma samples for factor VIII and factor VIII binding activity of von Willebrand factor (vWF). Of these plasma samples, 31 were cotested by 2 specialist centers using different detection procedures for vWF-factor VIII binding: there was good agreement between results obtained by chromogenic assay and enzyme-linked immunosorbent assay. In total, 8 patients with type 2N vWD were identified. The 2-stage factor VIII assay detected a deficiency of factor VIII relative to vWF antigen in all 8 patients; the 1-stage factor VIII assay detected a relative deficiency in only 3 patients. Four patients were homozygous for the most common type 2N mutation (R854Q), 3 patients were presumed to be compound heterozygotes, and in 1 patient no type 2N mutations were identified. In this study of patients from 5 specialist centers in Australia, type 2N vWD was found in 5 families. The 2-stage factor VIII assay was more useful as a screening test than the 1-stage assay, and both vWF-factor VIII binding assays were equally effective.
authors.affiliation: Haemostasis Laboratory, Haematology Division, Institute of Medical and Veterinary Science, University of South Australia, Adelaide, Australia.
authors.forename: Susan E
authors.initials: SE
authors.lastname: Rodgers
authors.forename: Nancy V
authors.initials: NV
authors.lastname: Lerda
authors.forename: Emmanuel J
authors.initials: EJ
authors.lastname: Favaloro
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Duncan
authors.forename: Graeme J
authors.initials: GJ
authors.lastname: Casey
authors.forename: Diana M
authors.initials: DM
authors.lastname: Quinn
authors.forename: Mark
authors.initials: M
authors.lastname: Hertzberg
authors.forename: John V
authors.initials: JV
authors.lastname: Lloyd
mesh_terms: D000328:Adult; D000818:Animals; D001315:Australia; D002648:Child; D004797:Enzyme-Linked Immunosorbent Assay; D005169:Factor VIII / Q000032:analysis*; D005260:Female; D006801:Humans; D008297:Male; D011817:Rabbits; D012016:Reference Values; D014842:von Willebrand Diseases / Q000097:blood*; D014841:von Willebrand Factor / Q000032:analysis*
chemical_list: D014841:von Willebrand Factor; D005169:Factor VIII