The presence of the APOE-ε4 allele(s) is a strong risk factor related to the development of Alzheimer’s disease (AD) (e.g., odds ratio (OR) 5.9 in ε4/ε3 and OR 33.1 in ε4/ε4 in Japanese population) (Liu et al. 2013), especially of late-onset AD. Here, APOE is linked to Alzheimer disease.