Positron emission tomography (PET) imaging has greatly advanced our understanding ofthe emergence, distribution, and longitudinal accumulation of amyloid-beta(Aβ) plaques and tau-containing neurofibrillary tangles (NFT) in the brainsof living individuals, in the context of both ageing and Alzheimer’s disease(AD). Here, MAPT is linked to early-onset autosomal dominant Alzheimer disease.