CHRNB4 and Parkinson disease: The DEGs were further queried in the Drug Gene Interaction Database (DGIdb), a data mining platform for investigating the druggable genome for personalized treatment, to identify their interacting compounds.23 As shown in Fig. 5e–l, genes without reported effective PD therapeutic drugs were excluded, as well as genes that were inconsistent with RT-PCR verification results (Chrnb4, Aldh1a1, Drd2, Fkbp5).