Endothelial dysfunction, which is characterized by lower bioavailability of the vasorelaxing nitric oxide (NO) and increased production of the vasoconstricting endothelin-1 (ET-1), is, together with a dysregulated metabolism of low density lipoprotein (LDL) and high density lipoprotein (HDL), a key player in atherosclerosis onset and progression (8, 10–13). The gene discussed is EDN1; the disease is atherosclerosis.