MAPT and early-onset autosomal dominant Alzheimer disease: The neurological hallmarks of Alzheimer's disease (AD) are the presence of amyloid beta plaques, hyperphosphorylated tau aggregates, and neuronal loss – otherwise known as the ‘A/T/N’ criteria (amyloid/tau/neurodegeneration) – although the addition of other relevant biomarkers is an active area of research [[72], [73], [74], [75]].