Meanwhile, the ɛ4 allele of the ApoE has been strongly confirmed as a genetic risk factor for sporadic AD (Raber et al., 2004; Loy et al., 2014), with the other two isoforms, ɛ2 and ɛ3, respectively, decreasing the likelihood of AD or having a neutral effect. The gene discussed is APOE; the disease is Alzheimer disease.