Variant von Willebrand's disease. A study emphasizing crossed-immunoelectrophoresis

30 members of an Illinois kindred were studied with a battery of haemostatic tests including the template bleeding time, platelet retention by glass beads (PRGB), measurement of activities related to factor VIII, and crossed-immunoelectrophoresis (CIEP). 9 family members had a history of excessive bleeding, and all 9 had prolonged bleeding times and increased migration of their factor VIII-related antigen (VIIIR:Ag) on CIEP. Of the other tests performed, the VIII:Ristocetin Cofactor and the PRGB showed the best correlation with the bleeding time. 3 subjects who were not bleeders, but who came from a branch of the family where there were several affected members, also had an abnormal VIIIR:Ag. The pattern of inheritance of the altered VIIIR:Ag in this family was one of autosomal dominance with full penetrance. The CIEP is a valuable screening test for the detection of variant von Willebrand's disease and the recognition of silent heterozygotes.