MAPT and Alzheimer disease: Recent studies in humans also indicate that tau is becoming phosphorylated earlier than expected, as plasma levels of tau phosphorylated at threonine 217 (pT217Tau) is an emerging, early biomarker that heralds future AD (Barthélemy et al., 2024; Mendes et al., 2024; Palmqvist et al., 2020; Pandey et al., 2025).