RTN3 has been identified in the mouse brain, kidney, liver, lung, testis, and ovary, especially the brain, and its aberrant expression is associated with obesity, hypertriglyceridemia (HTG), chronic kidney disease, and hepatocellular carcinogenesis.10, 12, 15, 16. The gene discussed is RTN3; the disease is obesity due to melanocortin 4 receptor deficiency.