Plasma SOD activity was not significantly different by diabetic nephropathy status: 2.95±0.19 (n = 130) vs 2.98±0.21 (n = 81) vs 3.01±0.17 (n = 160) mU/l for subjects without nephropathy, or with incipient or established/advanced nephropathy, respectively (p = 0.97, mean ± SEM, ANCOVA adjusted for sex, age and use of ACE inhibitors). The gene discussed is SOD1; the disease is diabetic kidney disease.