Together, our results indicated that the expression levels of 14 hub genes (SLC18A2, SLC6A3, KCNJ6, FOXA2, NR4A2, CACNA1E, DRD2, RET, EN1, FGF13, SYNGR3, RIMBP2, KCNB1, and RAB3C) were decreased in SN tissues of PD samples. Here, DRD2 is linked to Parkinson disease.