MAPT and Alzheimer disease: The proper function of the brain has been linked to the acetylcholine activities in the brain [29]; therefore, an increase in the acetylcholine in the neurotransmission process will improve the memory of a patient, although Madav et al. [30] have described various attempts that were investigated by other researchers which targeted amyloid β accumulation, and tau protein hyperphosphorylation, and these investigations have not yet resulted in any FDA-approved drug for the treatment of Alzheimer's disease.