Management of an uncommon form of type 2M VWD: A single centre experience

We report a single centre's experience of the diagnosis and management of an uncommon form of type 2 von Willebrand disease (VWD) in members of two unrelated families. The affected patients presented with mild to moderate bleeding phenotypes and accompanying MCMDM-1 VWD bleeding assessment tool scores of 5 or less. Genetic analysis in both families confirmed a missense mutation in exon 30 of the von Willebrand factor (VWF) gene, a single base substitution T>A at nucleotide 5282 which led to change at codon 1761 from methionine to lysine (M1761K). This mutation lies within the A3 domain of the VWF protein, a region that is important for collagen binding. All affected patients were found to have normal coagulation profiles, normal VWF multimers and normal VWF assays except the VWF collagen-binding (VWF: CB) assay levels, which were significantly reduced. Desmopressin effected a good response in all treated patients, with a 3- to 5-fold rise of VWF:CB levels. However, there was variability in the degree to which VWF:CB levels remained elevated. Surgical procedures, including the delivery of one patient, were able to be managed with either desmopressin and/or tranexamic acid alone, with little need for recourse to VWF factor concentrate therapy.