The apolipoprotein E ε4 allele (APOE-ε4) is a key gene associated with sporadic AD, and is one of the major risk factors for AD (Corder et al., 1993; Strittmatter et al., 1993; Genin et al., 2011; Verghese et al., 2011). This evidence concerns the gene APOE and Alzheimer disease.