MAPT and Alzheimer disease: Threonine 181 is one site that is subject to tau hyperphosphorylation, and the resulting P-tau181 directly contributes to neurofibrillary tangle formation in the brain.33 We demonstrated that P-tau181 outperformed the other single plasma biomarkers in identifying Alzheimer’s disease patients whose diagnosis was confirmed by amyloid PET with an AUC of 0.996.