VWD type 1 is associated with increased PNA binding. VWF antigen levels (A) and PNA binding (B) were determined in plasma samples of healthy volunteers (n = 111), unaffected family members (n = 15), and patients diagnosed with VWD type 1 (n = 32). Data represent the mean of 2 independent determinations, and variance between measurements was 12% or less (VWF antigen levels) and 16% or less (PNA binding). (C) PNA binding versus VWF antigen levels is depicted: Depicted are healthy volunteers (□), unaffected family members (▴), and VWD type 1 patients (○). Bars represent mean values.