MAPT and Alzheimer disease: Sarkosyl-insoluble tau extracted from AD cases yielded also complex CSA profiles with 50% of tau conformers unfolding (fractional change of unfolding (Fapp) values of 0.5) between 1.3 and 1.8 M Gdn HCl with exception of AD6 with 3 M Gdn HCl to reach 50% unfolding.