NEW FAMILIES WITH VON-WILLEBRAND DISEASE TYPE 2M (VICENZA)

The variant von Willebrand disease (vWd) variant type 2M (Vicenza) was identified in 13 patients of 7 unrelated families. 11 patients were f rom different parts of Germany and 2 patients from Turkey. Hitherto th is variant of vWd has been described only in two families originating from the province of Vicenza in Northern Italy. Characteristically thi s type of vWd shows the supranormal multimers of von Willebrand factor (vWf) in plasma similar to those seen in normal plasma after desmopre ssin infusion. Clinically, the patients present with bleeding symptoms . Other laboratory abnormalities include reduced values for vWf antige n (vWf: Ag), factor VIII coagulant activity (VIII:C), ristocetin cofac tor activity (RiCof) and collagen binding activity (vWf: CBA). The her editary transmission of this variant is consistent with an autosomal d ominant mode of inheritance. The patients with vWd type 2M (Vicenza) c ould be allocated into two subgroups: type ''platelet normal'' with no rmal vWf properties in platelets and type ''platelet low'' with reduce d vWf: Ag levels in platelets. (C) 1997 Elsevier Science Ltd.