MAPT and supranuclear palsy, progressive, 1: Cryo-EM ultrastructural evaluation of tau fibrils studies show that among tauopathies, CBD, AGD, and ARTAG fibrils have more structural resemblance (four-layered fold), while PSP fibrils are similar to those of GGT (three-layered fold), and PART and AD fibrils are identical (16).