To explore the possibility of a synergistic effect between oxidative cellular conditions induced by the oxidation of DA and α-synuclein in PD, we investigated how wild-type (WT) α-synuclein or its A30P pathogenic mutant influences DA toxicity in a dopaminergic human neuroblastoma BE(2)-M17 cell model stably over-expressing α-synuclein. This evidence concerns the gene SNCA and Parkinson disease.