An exploratory immunoprecipitation–mass spectrometry (IP‐MS) experiment using HT7 antibody (epitope aa159–163, reacting with all tau isoforms and both phosphorylated and non‐phosphorylated tau species) in AD and control pools showed that mono‐phosphorylated tryptic peptides containing p‐tau181, p‐tau217 and p‐tau231 were among the four most relevant p‐tau species in terms of relative abundance (signal intensity) (Fig 1A). Here, MAPT is linked to Alzheimer disease.