SNCA and Parkinson disease: The pathological hallmarks of PD are a loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc) and the presence of fibrillary cytoplasmic inclusions, known as Lewy bodies containing α-synuclein, which eventually extend to limbic and neocortical brain regions, consequently decreasing brain dopamine (DA) levels and leading to a severe deterioration of cognitive functions [3].