MAPT and early-onset autosomal dominant Alzheimer disease: Cognitive tests, patient age, MRIs for evaluating brain structural and functional integrity, invasive CSF biomarkers for quantifying tau levels and amyloid, fluorodeoxyglucose positron emission tomography (FDG PET) region of interest (ROI) averages for assessing metabolism in cells, AV45 PET ROI averages for measuring amyloid-beta load in the brain, and DTI ROI for analyzing microstructural parameters of axons and other biomarkers (such as APOE status, demographic information, diagnosis) are predominantly utilized in clinical practice to identify the stage of Alzheimer’s disease.