title: Evaluation of an automated screening assay for von Willebrand disease type 2N.
abstract: Evaluating the factor VIII (FVIII) binding activity of von Willebrand factor (VWF) is an important step in the diagnostic work-up of families affected by apparent mild haemophilia A. In von Willebrand's disease (VWD) type 2N (Normandy), mutations at the N-terminal end of the mature VWF subunit gene prevent the binding of FVIII. Individuals heterozygous for type 2N VWD are generally asymptomatic. Homozygotes and compound heterozygotes present with a clinical picture which mimics haemophilia A, with a markedly reduced FVIII : C activity and VWF within the normal range, but instead of exhibiting X-linked inheritance they show an autosomal recessive inheritance pattern. The distinction between haemophilia A and VWD type 2N has important implications for therapy and genetic counselling. We present a highly specific enzyme-linked immunosorbent assay screening method for the Normandy variant, which measures VWF : FVIII binding activity in parallel with VWF antigen, using monoclonal capture and detection antibodies. The assay is fully automated using a robotic microtitre plate processor, requiring minimal user intervention and providing the capacity to screen large numbers of patients.
authors.affiliation: The Haemophilia Reference Centre, St Thomas' Hospital, London, UK. thestevetaylor@yahoo.co.uk
authors.forename: S L
authors.initials: SL
authors.lastname: Taylor
authors.forename: E
authors.initials: E
authors.lastname: Bromidge
authors.forename: G F
authors.initials: GF
authors.lastname: Savidge
authors.forename: A
authors.initials: A
authors.lastname: Alhaq
mesh_terms: D001331:Automation; D003937:Diagnosis, Differential; D004797:Enzyme-Linked Immunosorbent Assay / Q000295:instrumentation; D005169:Factor VIII / Q000378:metabolism; D005808:Genes, Recessive; D005820:Genetic Testing / Q000379:methods*; D005838:Genotype; D006467:Hemophilia A / Q000175:diagnosis; D011485:Protein Binding; D014842:von Willebrand Diseases / Q000145:classification / Q000175:diagnosis*; D014841:von Willebrand Factor / Q000032:analysis* / Q000235:genetics
chemical_list: D014841:von Willebrand Factor; C069815:von Willebrand factor Normandy; D005169:Factor VIII