Identification of CFHR proteins deficiencies in serum samples. Serum samples from control persons, patients with aHUS, and patients with GN were analyzed by SDS-PAGE and Western blot analysis by using 3 different antibody preparations (A-C) that recognize fH and CFHR proteins. Labels on the top of each gel refer to the 5 CFHR patterns observed: the most frequent pattern in which all the CFHR proteins analyzed are present (Normal), and 4 additional patterns showing different CFHR deficiencies (DefR1R3, DefR1, DefR1R4A, and DefR3). The serum samples chosen to illustrate the 5 patterns correspond to the control sample C1 and to the patients with aHUS H13, H119, H177, and H123, respectively. The position and size (kDa) of the molecular weight markers are shown to the left of gel A. The lane showing the DefR3 pattern in panel C has been repositioned.