In diabetes mellitus (DM), there is activation of the intrarenal renin‐angiotensin system (RAS) through the renal uptake of prorenin and angiotensinogen (AGT), increased Angiotensin-converting enzyme (ACE) immunostaining in tubular and interstitial cells, elevated levels of angiotensin II (Ang II), and enhanced intrarenal AGT mRNA and/or protein levels [1–3]. The gene discussed is REN; the disease is diabetes mellitus.