MAPT and Alzheimer disease: We have been investigating the sarkosyl-insoluble pathological tau proteins prepared from brains of patients with AD, PiD, CBD, PSP, or and FTDP-17T (intron 10 + 16), and we previously reported that the carboxyl-terminal region of tau (residues 243–406), which constitutes the trypsin-resistant core units of tau aggregates, shows different banding patterns among the diseases (Taniguchi-Watanabe et al., 2016).