MAPT and Alzheimer disease: Although the currently available cerebrospinal fluid (CSF) biomarkers for AD [i.e., amyloid β (Aβ), total Tau (t-Tau), and phosphorylated Tau (p-Tau) (2, 3)] have a high sensitivity and specificity for AD, there is still no test to effectively predict the development of AD in a pre-symptomatic stage (4).