Several studies have linked CST3 gene polymorphisms with an increased risk of developing AD (Crawford et al., 2000; Finckh et al., 2000; Beyer et al., 2001; Olson et al., 2002; Lin et al., 2003; Goddard et al., 2004; Cathcart et al., 2005; Bertram et al., 2007) and a possible interaction with APOE genotype was noted. This evidence concerns the gene APOE and Alzheimer disease.