CFH and acute kidney injury: In 17 patients (81%), a defect in complement regulation was found by either a proven or likely pathogenic mutation or a rare variant of uncertain pathogenicity (variant of uncertain significance) in one of the complement regulatory genes or by antibodies against factor H. These patients presented after an evident triggering event and could be classified as definite aHUS (AKI and TMA) (Supplementary Tables S1 and S2).