Nevertheless, it is known that Aβ accumulation begins 15–20 years before cognitive impairment and leads to the generation of hyperphosphorylated tau protein and neurofibrillary tangle (NFT), and that people with senile plaque accumulation or decreased cholinergic nerve fibers are at high risk of developing AD (preclinical AD) even if they do not show cognitive impairment (Jacobs et al., 1995; Beach et al., 1997; Jack et al., 2010). The gene discussed is MAPT; the disease is Alzheimer disease.