An imbalance between production and clearance of Aβ occurs early in AD and is typically followed by the accumulation of tau (T in A/T/N) protein tangles (another key pathological hallmark of AD) and neurodegeneration (N in A/T/N) detectable on brain MRI scans (Hardy and Selkoe, 2002; Sperling et al., 2011; Jack et al., 2016). Here, MAPT is linked to Alzheimer disease.