CFHR1 and atypical hemolytic-uremic syndrome: The activity of the FHRs antagonizing the regulatory role of FH (de-regulation activity) was initially described in humans to explain the association of FHR-1 and FHR-5 mutants with C3-glomerulopathy (C3G) (8, 9) and extrapolated to mutants associated with atypical hemolytic uremic syndrome (aHUS) and to the wild-type FHRs (10).