Several AD biomarkers have been studied including the deposition of pathological amyloid (Aβ) and tau in the cerebrospinal fluid (CSF) [31], the brain metabolic change derived from fluorodeoxyglucose positron emission tomography (FDGPET) [32], and the structural change in the brain morphology measured from the magnetic resonance imaging (MRI) [33]. This evidence concerns the gene MAPT and Alzheimer disease.