Four major genetic loci have been related to AD, APOE (Apolipoprotein E) on chromosome 19, APP (Amyloid precursor protein) on chromosome 21 (3), PSEN1 (Presenilin-1), and PSEN2 (presenilin-2) on chromosome 14 and 1, respectively (4–8). This evidence concerns the gene APOE and Alzheimer disease.