When studying MetS and the corresponding CAD, multiple transgenic models exist, including Leptin-deficient (Lep ob/ob), Leptin receptor-deficient (LepR db/db) mice Low-density lipoprotein receptor knockout (Ldlr−/−), and Apolipoprotein E-deficient (ApoE−/−) mice. This evidence concerns the gene APOE and metabolic syndrome.