In AD, pathologically aggregated tau spreads in a prion-like manner following a stereotypical pattern, originating in the locus coeruleus and transentorhinal cortex (Braak stage I–II), subsequently spreading to the limbic system (Braak stage III–IV) and the neocortex (Braak stage V–VI)7. The gene discussed is MAPT; the disease is Alzheimer disease.