Hence, the demonstration of the specific involvement of Wnt1 signaling components in the adult PD-injured midbrain associating with mDAergic neuronal cell death and self-repair in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of basal ganglia injury uncovered, for the first time, a novel role for Wnt/β-catenin’s main actors in the maintenance and protection of mDA neurons in the adult and aged PD mesencephalon [49,50]. This evidence concerns the gene WNT1 and Parkinson disease.