The traditional understanding of PD as a movement disorder centres on dopaminergic neuronal loss in the substantia nigra pars compacta (SNPC) [8], as typically demonstrated by a macroscopic reduction in neuromelanin pigmentation and microscopically confirmed by decreased immunoreactivity for dopaminergic neuronal markers: tyrosine hydroxylase (TH, an essential enzyme in dopamine synthesis) and dopamine transporter (DAT, responsible for dopamine reuptake and recycling) [9]. This evidence concerns the gene SLC6A3 and Parkinson disease.