After checking the gene networks involved in the pathogenetic pathway of Parkinson’s disease, we selected six genes, including PPP1R15A (protein phosphatase 1 regulatory subunit 15A), TMEM40 (transmembrane protein 40), GADD45B (growth arrest and DNA damage-inducible beta), GADD45A (growth arrest and DNA damage-inducible alpha), DNAJB1 (DnaJ heat shock protein family 40 member B1), and GABARAPL1 (GABA receptor-associated protein-like 10) for further investigation. The gene discussed is GADD45A; the disease is Parkinson disease.