Figure 4. .

Analysis of FXII activity in plasma from patients with HAE type III. a, Relative FXII amidolytic activity in plasma from HAE type III and healthy individuals (control), determined using the FXIIa-specific chromogenic substrate S-2303. Substrate turnover was measured photometrically via absorbance at a 405-nm wavelength. Data are presented in box-and-whisker plots showing the median (dark line in the box), 25th–75th percentiles (box), and 5th–95th percentiles (whiskers). b, Time course of S-2303 turnover in plasma of a representative patient with HAE type III (“French fam, IV:01”) from the French family, in the absence or presence of the FXIIa inhibitor PCK (2 mM) and in a patient with HAE type III (“F10, IV:11”) from German family F10. For comparison, FXII substrate cleavage in a plasma sample from a healthy control is plotted. Whereas FXII amidolytic activity is markedly increased because of the p.Thr328Lys mutation in the French patient, FXII activity is normal in the German patient.