MAPT and Alzheimer disease: Research criteria for AD includes cerebrospinal fluid (CSF) pathophysiological markers (Dubois et al., 2014): low CSF Aβ1–42 concentration reflects the brain amyloid burden, high Total-Tau (T-Tau) CSF concentration reflects the intensity of neuronal loss and high Phosphorylated-Tau (P-Tau) is believed to be a direct marker of tangle pathology.