Pedigrees and laboratory data of 4 families with type 1 VWD. Pedigrees are shown for 4 families, A, B, C, and D. Affected individuals are represented by half-filled symbols, unaffected individuals by gray symbols, and those with an unknown phenotype are denoted by white, unfilled symbols. In some cases, diagnosis was based on historical data and the laboratory data are unavailable, and these patients are denoted by **. The laboratory test results are listed as follows: Patient ID; blood type (TY = too young); FVIII:C, VWF:Ag, VWF:RCo, and multimer status (Nl = normal). Laboratory parameters are characteristic of type 1 VWD in all 4 families.