MAPT and Alzheimer disease: The discovery of new causal AD drugs can be expected, primarily in the field of neurodegeneration regulators related to (i) inhibition of the formation of toxic Aβ oligomers, regulation of APP production and proteolysis, removal of Aβ from the brain, and regulation of signaling pathways activated by Aβ oligomers; (ii) synthesis, phosphorylation, and aggregation of tau; (iii) affecting mitochondrial biogenesis, transport, dynamics, and function; and (iv) regulating the activity of neuronal survival signaling pathways, such as the PI3K/Akt/mTOR pathway and other neuroprotective pathways.