The markedly higher p-tau217 levels with no aggregation or tangle formation in newborns compared to Alzheimer’s disease suggest distinct physiological processes governing tau phosphorylation during development versus neurodegenerative disease.2 It is still unknown if different p-tau markers show different increases and trajectories in newborns like they do in Alzheimer’s disease. Here, MAPT is linked to early-onset autosomal dominant Alzheimer disease.