A Retrospective Study to Evaluate the Clinical Outcome According to Treatment in aHUS Patients in South Korea

Primary objective \- To determine the clinical prognosis by identifying the disease course and severity by treatment with or without eculizumab in patients with aHUS in Korea. Secondary objectives * To determine the clinical prognosis of the disease in all patients with aHUS in Korea. * To determine the clinical prognosis of the disease in patients diagnosed with aHUS prior to the initiation of eculizumab reimbursement system in Korea. * To determine the treatment responses by treatment options in patients with aHUS in Korea. * To identify risk factors that affect mortality in all patients with aHUS in Korea. * To investigate the recurrence and clinical prognosis in patients with aHUS in Korea when eculizumab is discontinued