Evidence of oxidative stress in familial amyloidotic polyneuropathy type 1

Objective: To evaluate the oxidative state in patients with familial amyloidotic polyneuropathy type 1 (FAP1). Design: From 3 unrelated families, patients with FAP1 carrying a transthyretin,Met 30 mutation were studied. The diagnosis was confirmed by genetic analysis. Eleven of 21 patients carried the mutation; all were symptomatic and were clinically assessed using a clinical score. All of the patients were evaluated for copper-zinc superoxide dismutase type I activity in red blood cells using spectrophotometry. Plasma total reactive antioxidant potential was studied using a chemiluminescent method. The results were compared with those obtained from an age-matched, control group.. Setting: A public and academic multidisciplinary research clinic. Results: Six of the 11 FAP1-positive patients disclosed superoxide dismutase type I activity values greater than 55 U/mg of protein (upper control limit), whereas 9 of 10 patients in whom total reactive antioxidant potential was measured had values below the lower limit of the control group. No relationship was found between the levels of superoxide dismutase type I activity and the severity of the clinical involvement. Conclusions: Oxidative stress may be part of the mechanisms leading to tissue damage in patients with FAP1. The lack of correlation between the laboratory findings and the severity of clinical involvement may signal that oxidative processes are at work throughout the natural history of the disease.