The analytical methods for tauPTM characterization include neuroimaging,biosensing, immunoassay, and mass spectrometry (MS) techniques.10,11 Among them, immunoassay, which is simple to implement and providessemiquantitative information, has been the workhorse for the identificationand quantification of tau or phosphorylated tau (p-tau).12 However, the antibody-based targeted approachimpedes the discovery of new PTMs that could be critical for AD progression. Here, MAPT is linked to Alzheimer disease.