In the setting of sporadic AD, tau aggregates are thought to initiate in subcortical structures, namely the locus ceruleus, before stereotypical progression of neurofibrillary degeneration into limbic regions, including the transentorhinal cortex and hippocampus, followed by broader neocortical involvement codified as the Braak stages of AD (2, 3). The gene discussed is MAPT; the disease is Alzheimer disease.