EN1/2 expressed in the mDA neurons from the SNpc and Ventral Tegmental Area (VTA) mDA neurons exerts pro-survival activity in these cells as demonstrated by their progressive retrograde degeneration in the En1 heterozygote mouse (En1-Het), associated with Parkinson-Disease (PD)-like motor and non-motor phenotypes (Sonnier et al., 2007; Nordströma et al., 2015). This evidence concerns the gene EN1 and Parkinson disease.