Studies showing very high (AUC 0.98) ability of plasma pT217 to discriminate Alzheimer’s disease from other neurodegenerative disorders [43], stronger correlation of pT217 than pT181 with tau PET [14], CSF and IP-MS data showing a higher magnitude of increase of plasma pT217 and stronger association with Aβ PET than pT181 [17], and CSF pT231 increasing at the early stage of the disease suggest that there may be disease associated differences across these pTau species and that measurement of specific phosphorylated species may be useful to track disease progression. Here, MAPT is linked to early-onset autosomal dominant Alzheimer disease.