Absence of abnormal erythrocyte superoxide dismutase, copper, or zinc levels in patients with retinitis pigmentosa.

Blood samples obtained from 22 patients with retinitis pigmentosa, 6 unaffected family members, and 8 unrelated controls showed serum copper and zinc to be in the normal range, contrary to the results in earlier reports. Likewise no significant variation of erythrocyte superoxide dismutase (SOD) and catalase levels was found between the 3 groups or when the patients were grouped by sex, age, or genetic distribution. The SOD proteins from controls and retinitis pigmentosa patients had identical mobilities on gel electrophoresis, isoelectric points, and heat stabilities. Our studies do not support the use of copper, zinc, or SOD in the diagnosis or treatment of retinitis pigmentosa.