Genome-wide Association Studies (GWAS) have implicated many Single Nucleotide Polymorphisms (SNPs) (Kunkle et al., 2019), of which the apolipoprotein e4 allele (APOE4) confers the greatest risk (Saunders et al., 1993; Strittmatter et al., 1993; Farrer et al., 1997; Lambert et al., 2013; Yu et al., 2014), but is neither necessary nor sufficient to cause AD (Sims et al., 2020). This evidence concerns the gene APOE and Alzheimer disease.