Portal hypertension is a major complication in liver disease caused by increased intrahepatic vascular resistance mediated in part by a reduction in eNOS derived NO (Iwakiri and Groszmann, 2007); cirrhotic livers also present with significantly reduced hepatic eNOS activity (Rockey and Chung, 1998; Shah et al., 1999), while NAFLD patients across varying degrees of severity show marked hepatic eNOS dysfunction (Persico et al., 2017). The gene discussed is NOS3; the disease is liver disorder.