In humans, Apolipoprotein E (APOE) exists as three major allelic variants (APOE2, APOE3 and APOE4), and it is the major genetic determinant of susceptibility to development of late-onset AD (Coon et al., 2007; Corder et al., 1994; Farrer et al., 1997; Saunders et al., 1993). This evidence concerns the gene APOE and Alzheimer disease.