Microglia in the uninflamed brain exhibit a homeostatic genetic signature, expressing mRNAs for P2ry12, Cx3cr1, Temem119, Siglech, Hexb, and Fcrls, which are all downregulated during aging and in neurodegenerative diseases associated with cognitive disruption [60, 61]. This evidence concerns the gene P2RY12 and neurodegenerative disease.