The activation of microglia in the brain occurs through many triggers like aggregated α-synuclein, pesticides, MPTP, bacterial lipopolysaccharide (LPS), and cytokines, which have implications in dopaminergic neuronal death in PD as observed in different experimental systems (Sanchez-Guajardo et al., 2015; Caggiu et al., 2019; Lee et al., 2019; Zhao et al., 2019). The gene discussed is SNCA; the disease is Parkinson disease.