Clinical trials of passive amyloid-β immunotherapy are currently in progress in groups at high risk of developing Alzheimer’s disease, including those with a familial autosomal dominant form of the disease due to PSEN1 mutation or APOE ɛ4 homozygotes (Prevention and Generation studies) (The Lancet, 2012; National Institute on Aging, 2016). Here, APOE is linked to early-onset autosomal dominant Alzheimer disease.