The truncated repeat-domain fragment of tau spanning residues 297–391 (referred to as dGAE (see [[33], [34], [35], [36], [37]] for nomenclature)), which was first identified biochemically in proteolytically stable PHF core preparations from AD brain tissues [[35], [36], [37]], includes the core sequence (306–378) characterised by cryo-electron microscopy as forming C-shaped subunits assembled to form a combined cross-β/β-helix structure [38]. The gene discussed is MAPT; the disease is Alzheimer disease.