Flow cytometric analysis. Flow cytometric analysis was performed on washed, paraformaldehyde-fixed platelets from a normal individual, the patient, and her parents. The platelets were reacted with normal mouse IgG, anti-GPIIb/IIIa complex antibody (HPL1), anti-GPIbα antibody (HPL7), anti-GPIX antibody (SZ1), or anti-GPV antibody (SW16), followed by fluorescein-labeled goat anti-mouse IgG. The number in each panel indicates the mean fluorescence intensity.