In this context, amyloid peptide 1–42, total Tau protein, and phosphorylated Tau in cerebrospinal fluid, positron-emission tomography (PET) with amyloid tracers, fluorodeoxyglucose-PET (FDG-PET) and structural brain magnetic resonance imaging (MRI) seem to be able to identify the pathological process of AD in the preclinical phase [19]. The gene discussed is MAPT; the disease is Alzheimer disease.