A common leucine7-to-proline7 polymorphism in the single peptide of the NPY gene was found to be associated with increased stress-induced plasma NPY levels, hyperlipidaemia, compromised low-density lipoprotein cholesterol metabolism as well as accelerated atherosclerosis, hypertension and coronary heart disease (Niskanen et al., 2000; Karvonen et al., 2001). This evidence concerns the gene NPY and hyperlipidemia.