Different bleeding risk in type 2A and 2M von Willebrand disease: a 2‐year prospective study in 107 patients

Background: Type 2A and 2M von Willebrand disease (VWD2A and VWD2M) are characterized by the presence of a dysfunctional von Willebrand factor (VWF) and a variable bleeding tendency. So far, a head‐to‐head comparison of the clinical history and bleeding risk between VWD2A and VWD2M has never been provided in a prospective manner. Aim of the study: We assessed the bleeding incidence rate and clinical characteristics in two cohorts of 17 families (46 patients) with VWD2A and 15 families (61 patients) with VWD2M prospectively followed‐up for 24 months. VWF gene mutations were characterized in all of them. Results: Mean bleeding score (BS) and VWF antigen at enrollment were significantly higher in VWD2A patients (P = 0.007). No correlation between VWF activity or factor VIII levels and the severity of BS was observed. The incidence rate of spontaneous bleeding requiring treatment was 107/100 patient‐years (95% CI, 88.3–131) in VWD2A compared with 40/100 patient‐years (95% CI, 30–53) in VWD2M (P