Investigation of a kindred with a new autosomal dominantly inherited variant type von Willebrand's disease (possible type IID).

A further type II variant of von Willebrand's disease has been identified in five family members who have the clinical symptoms of von Willebrand's disease. This variant is characterised by loss of high molecular weight VIIIR:AG multimers and the replacement of the normal triplet multimer configuration by a single dense band. In addition, variable minor bands are seen. These variants appear similar to those recently reported by Kinoshita et al and designated as type IID.