MAPT and Alzheimer disease: Aβ peptide is the key factor in AD pathogenesis and fibrogenesis of Aβ peptide, triggers a cascade of events such as hyperphosphorylation of tau and NFT formation, ER stress, disruption in Ca2+ homeostasis, mitochondrial dysfunction, microgliosis and astrogliosis inducing neuroinflammation eventually leading to neuronal death [14].