In particular, the ε4 allele of the Apolipoprotein E (APOE4) gene stands out as the most significant genetic risk factor for late-onset AD; the ε2 allele has been identified as neuroprotective (Van Cauwenberghe et al., 2016; Corder et al., 1994; Corder et al., 1993). This evidence concerns the gene APOE and Alzheimer disease.