If the microglia overwhelmed by stimulation such as lipopolysaccharide (LPS), interferon-gamma (IFN-α), or tumor necrosis factor-alpha (TNF-α), NO, excessive cytokines, and ROS are secreted, causing neurotoxicity and destroying brain tissue, causing degenerative brain diseases such as Alzheimer’s, Parkinson’s disease, and Croyfeldt–Jakob disease [4,5,6]. The gene discussed is TNF; the disease is Parkinson disease.