MAPT and Creutzfeldt Jacob disease: Aβ42/p‐Tau in both CSF and serum showed better accuracy (AUC = 0.9443 and 0.8159, respectively) to distinguish rpAD from AE group, and Aβ42/t‐Tau in both CSF and serum were able to distinguish AE from rpAD and CJD groups.