SOD1 and Nephropathy: However, in the subset of subjects with established/advanced nephropathy, the risk genotype of rs4880 was associated with significantly lower plasma SOD activity: 2.38±0.26 (TT) vs 3.04±0.15 U/ml (CT/CC), p = 0.008 (ANCOVA, adjusted for sex, age and use of ACE inhibitors).