Genome-wide association (GWAS) studies have determined a comprehensive list of genes associated with AD, including those that encode for apolipoprotein E (APOE) [11], death-associated protein kinase 1 (DAPK1) [12], interleukin 8 (IL8) [13], transferrin [14], and sortilin-related receptor (SORL1) [15]. Here, APOE is linked to Alzheimer disease.