Understanding the mechanisms of endothelial dysfunction in glomerular disease can be complex, because endothelial regulation and protection involve participation of the complement system, factors related to angiogenesis, the renin–angiotensin system (RAS), endothelin, the glycocalyx, the coagulation cascade, interaction between these pathways, interactions between glomerular structures (the endothelium, mesangium, podocyte, and basement membrane) and interstitial structures (tubules, arterioles and small vessels) (1). The gene discussed is REN; the disease is glomerular disorder.