The presence of astroglia activation in AD [23▪▪,24▪▪,25▪▪], as well as in non-AD disorders, such as multiple sclerosis and frontotemporal lobar degeneration, support the use of plasma glial fibrillary acidic protein (GFAP) as a blood biomarker [26,27▪]. The gene discussed is GFAP; the disease is Alzheimer disease.