APOE and early-onset autosomal dominant Alzheimer disease: Despite the different age profiles of the two groups, individuals within them who will go on to develop Alzheimer’s disease may be at similar points along the preclinical continuum: FAD mutation carriers were on average 7 years before expected symptom onset, and Insight 46 participants (age, ∼70 years) were around a decade away from the average age of onset of sporadic Alzheimer’s disease [76 years in APOE-ε4 homozygotes, 84 years in ε4-non-carriers (Liu et al., 2013)].