MAPT and Alzheimer disease: In this regard, there are significant recent advances in the development of site-specific phosphor-tau biomarkers, such as p-tau181 and p-tau217 for blood- or CSF-based AD diagnosis (Blennow et al., 2015; Janelidze et al., 2020; Thijssen et al., 2021; Leuzy et al., 2022).