SOD1 and Spinocerebellar ataxia type 3: The ROS marker DCFH-DA was higher in the symptomatic SCA3/MJD individuals; the activity of the antioxidant enzyme GSH-Px was lower in the symptomatic SCA3/MJD group and was associated with the disease severity; the presymptomatic carriers presented a higher activity of the antioxidant enzyme SOD than the symptomatic SCA3/MJD patients.