Plasma MDA concentrations were higher in the AD group than in the NC group (p = 0.003), whereas plasma SOD levels were lower in the AD (p < 0.001) and aMCI (p = 0.045) groups than in NC, and GSH‐Px activity were higher in the AD group than in the aMCI group (p = 0.007). The gene discussed is SOD1; the disease is Alzheimer disease.