Interestingly, SIRT3 is called a longevity gene due to its negative correlation with hypertension, obesity and diabetes [15,16], and insufficiency of SIRT3 acts as a contributor to cardiac fibrosis [17,18], which strongly implicates SIRT3 as a crucial mediator between aging-associated diseases and cardiac fibrosis. The gene discussed is SIRT3; the disease is obesity due to melanocortin 4 receptor deficiency.