C5 and atypical hemolytic-uremic syndrome: Genetic deficiencies or abnormalities of FH lead to uncontrolled C3 activation and the accumulation of C3 and C5 activation products within the renal glomerulus [4] and cause the rare renal diseases C3 glomerulopathy (C3G) and atypical hemolytic uremic syndrome (aHUS) [5].