In PD mouse models, imbalance of NTN-1 and DCC is found to be a common feature in nigral DA neurons in which the well-established chemical PD inducer MPP+ (1-Methyl-4-phenyl pyridinium iodide) inhibits the expression of Netrin-1 but increases DCC expression in both concentration- and time-dependent manners (Hua et al., 2023). This evidence concerns the gene NTN1 and Parkinson disease.