Preclinical models have identified an upregulation of astrocytic mGlu5 in several diseases including Alzheimer’s disease (Lim et al., 2013; Shrivastava et al., 2013), amyotrophic lateral sclerosis (Anneser et al., 2004; Vermeiren et al., 2006), and multiple sclerosis (Fulmer et al., 2014). The gene discussed is GRM5; the disease is Alzheimer disease.