MAPT and Alzheimer disease: Cerebrospinal fluid (CSF), plasma, and blood biomarkers used in AD diagnosis are Aβ42, Aβ42/Aβ40 ratio, phosphorylated Tau or phospho-Tau (P-Tau), total Tau (t-Tau), P-Tau ratio, neurofilaments, synaptic proteins, activated astrocytes, and inflammatory markers [17].