MAPT and Alzheimer disease: Among the different p-tau isoforms, plasma p-tau217 displays the highest performance in both the early detection of AD pathology as shown by cerebrospinal fluid (CSF), showing the highest fold increase compared to the isoforms 181 and 231, and in differentiating AD from other neurodegenerative diseases in cognitively unimpaired subjects (Janelidze et al., 2023; Ashton et al., 2024).