Total superoxide dismutase (SOD) and glutathione-S-transferase (GST) activities were increased in erythrocytes [23], total SOD was decreased in fibroblasts [34], manganese-SOD (Mn-SOD or SOD2) activity and mRNA increased [33] or decreased [34] in the fibroblasts of FRDA patients, copper–zinc SOD (Cu–Zn-SOD or SOD1) activity and mRNA decreased [34] or were similar to that of HC [33], and catalase (CAT) activity [33] was similar to that of HC in fibroblasts. Here, SOD1 is linked to Friedreich ataxia.