Variables for which this is likely to hold, and which therefore should be matched for, include the health state of the patient prior to the decision of eculizumab treatment, such as laboratory values (Hb, thrombocytes, LDH, etc.)and complications indicating HUS-severity, as well as other factors such as age, comorbidity, which other treatments were used, and if these were successful or not. The gene discussed is GSTM1; the disease is hemolytic-uremic syndrome.