Alzheimer’s disease is characterized by neuropathological hallmarks that consist of the accumulation of extracellular amyloid-β plaques and intracellular neurofibrillary tangles,1 which are composed of insoluble fibrillary deposits of hyperphosphorylated tau.2 In the last two decades, advances in neuroimaging techniques for the in vivo assessment of amyloid-β and tau have enabled a move towards a biological definition of the disease.3,4 To this respect, cognitive testing that can be reliably linked to biomarkers may play a crucial role in staging disease. This evidence concerns the gene MAPT and early-onset autosomal dominant Alzheimer disease.