MAPT and early-onset autosomal dominant Alzheimer disease: Alzheimer’s disease (AD) is characterized by a progressive cognitive decline linked to both the extracellular deposition of aggregated amyloid-β (Aβ) peptides into plaques and the intraneuronal aggregation of hyperphosphorylated tau (p-tau) proteins.1 AD risk depends on various genetic and environmental factors.2,3 Among protective factors, several epidemiological studies have reported an inverse relationship between caffeine intake and both age-related cognitive impairments and the risk of developing AD later in life (for reviews, see Flaten et al.,4 Cunha5 and Yelanchezian et al. 6).