Moderately decreased baseline blood pressure has been described in NOX1y/- mice in some studies,21 but not in others.48,49 We did not observe significant differences in blood pressure at 44 weeks between WT and NOX1-deficient mice, nor increase in arterial pressure in metabolic disease, which is consistent with previous reports.20,40 Nevertheless, increased aortic stiffness evoked by obesity and metabolic disease50 and possibly ameliorated by NOX1-deficiency may contribute to the cardiac phenotype. This evidence concerns the gene NOX1 and obesity due to melanocortin 4 receptor deficiency.