Krueger et al. found that the SOD-2 protein content showed a J-curve pattern with significantly lower values in the CKD group compared to healthy volunteers (HV) and a progressive reduction up to CKD stage 4, followed by higher SOD-2 protein content in the advanced stages of CKD, i.e., CKD5 with and without HD treatment [49]. The gene discussed is SOD2; the disease is chronic kidney disease.