Abstract

Three patients with severe Von Willebrand's disease are shown to be homozygotes. They were born from unaffected parents. New techniques using a factor-VIII-related antigen assay by the Laurell method and a ristocetin-induced platelet aggregation assay demonstrated abnormalities in these two tests in both parents of the probands. Factor-VIII-related of heterogotes could not be differentiated from normal factor-VIII-related antigen by the immunodiffusion technique, crossed immunoelectrophoresis, and filtration on a sepharose 4b column.