Renin–angiotensin–aldosterone system (RAAS) blockade with an angiotensin converting enzyme (ACE) inhibitor (ACEI) or angiotensin II type I receptor blocker (ARB) is the most widely used strategy to slow the progression of DKD in both type 1 diabetes mellitus [3] or T2DM [4, 5]. The gene discussed is REN; the disease is diabetes mellitus.