Reactive microglia in different brain regions accompanied by higher levels of pro-inflammatory cytokines, such as tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), and interferon-gamma (IFN-γ), suggest the involvement of microglia in neuroinflammation during the development of PD [71]. Here, IFNG is linked to Parkinson disease.