Although these clinical symptoms may be indicative of AD onset, definitive diagnosis requires the detection of three pathological hallmarks in the brain, namely, extracellular amyloid (plaques) composed of Aβ peptides (graded by Thal phases [11, 12]), intracellular neurofibrillary tangles (NFTs) formed by hyperphosphorylated tau (categorized through Braak staging [13–15]), and degeneration in brain regions such as the entorhinal cortex, hippocampus, and cerebral cortex during late stages of onset [7, 16]. This evidence concerns the gene MAPT and Alzheimer disease.