Of particular interest were GDNF, a NTF involved in DAn survival and PD pathology (Allen et al., 2013), platelet-derived growth factor subunit BB (PDGF BB), a PDGF subunit which is implicated in neurogenesis (Mohapel et al., 2005; Yang et al., 2013), as well as amyloid-beta precursor protein (APP), a protein important for neuronal growth and migration, neurogenesis, and synaptogenesis (Coronel et al., 2019). This evidence concerns the gene GDNF and Parkinson disease.