MAPT and early-onset autosomal dominant Alzheimer disease: FDG PET: asymmetric, right-predominant glycolytic hypometabolism affecting posterior parietal regions and precuneus. Alzheimer's disease biomarkers: Amyloid-β (1-42): 497 ng/dL (normal >562) Phosphorylated tau: 130 ng/dL (normal <66) Total tau: 1,015.9 ng/dL (normal <370)