We found that PD-related genes (Th, Drd2, Ddc, Pitx3, Slc18a2, Slc6a3, Sncaip, Ccdc62, and Fbxo7) constituted a leading-edge subset and showed strong downregulation in the 10th MPTP/p injection when the PD model was successful achievement. Here, DDC is linked to Parkinson disease.