Hemolytic uremic syndrome with dual caution in an infant: cobalamin C defect and complement dysregulation successfully treated with eculizumab

Background Hemolytic uremic syndrome (HUS) is a clinical syndrome characterized by hemolytic anemia, thrombocytopenia, and acute kidney injury. Atypical hemolytic uremic syndrome(aHUS) is a devastating disease with significant mortality and high risk of progression to end-stage kidney disease. It is mostly caused by dysregulation of the alternative complement pathway. CobalaminC (Cbl C) defect is a genetic disorderof cobalaminmetabolism and is a rare cause of HUS.