Many studies have consistently shown that core AD cerebrospinal fluid (CSF) biomarkers amyloid β (Aβ42 and Aβ42/Aβ40 ratio), total-tau (T-tau), and phosphorylated tau (P-tau) reflect key elements of AD pathophysiology and have high diagnostic value and high concordance with amyloid positron emission tomography (PET) [49]. This evidence concerns the gene MAPT and Alzheimer disease.