["The pathogenesis of Parkinson's disease (PD) involves both genetic susceptibility and environmental factors, with focus on the mutation in the alpha-synuclein gene (SNCA).Objective To analyse the polymorphism SNCA-A53T in patients with familial PD (FPD) and sporadic PD (SPD).", 'A total of 294 individuals were studied, regardless of sex and with mixed ethnicity. The study group with 154 patients with PD, and the control group included 140 individuals without PD. The genotyping of SNCA-A53T was performed by PCR/RFLP. Significance level was p < 0.05.', 'Among all patients, 37 (24%) had FPD and 117 (75.9%) had SPD. The absence of SNCA-A53T mutation was observed in all individuals.'] Is alpha-synuclein A53T mutation frequent on a sample of Brazilian Parkinson 's disease patients?