Von Willebrand Disease Subtype 2N

Von Willebrand disease subtype 2N is an autosomal recessive disorder in which the VWF D’D3-domain FVIII binding site is defective. Nearly 100% of FVIII circulates in a dynamic complex with normal VWF protected from activated protein C lysis. FVIIi, like carrier molecule VWF, has a 12-hour half-life. Uncomplexed FVIII in VWD subtype 2N has a circulating half-life of 2–4 hours. Consequently, VWF subtype 2N is sometimes nicknamed “autosomal Hemophilia A” because both males and females may display a range of classic hemophilia symptoms. While 2N may be diagnosed by genomic analysis, there is an effective phenotypic assay, VWF:FVIIIB. VWF:FVIIIB is an enzyme immunoassay that measures fixed rFVIII affinity for patient VWF. The assay is available in kit form and Mayo offers it as a lab-developed test under the rubric, VWD8B. Check your library for a current 2N review: Seidizadeh O, Peyvandi F, Mannucci PM: Von Willebrand disease type 2N: an update. J Thromb Haemost. 2021;19:909–16. doi: 10.1111/jth.15247.