Therefore, the deficiency of functional α-synuclein might compromise the efficiency of synaptic transmission, and thus, contributes to the nigrostriatal system disfunction in PD patients (Al-Wandi et al., 2010, Benskey et al., 2016, Collier et al., 2016, Venda et al., 2010). This evidence concerns the gene SNCA and Parkinson disease.