Transforming growth factor (TGF-β) and connective tissue growth factor (CTGF) are well-known profibrotic factors that can stimulate synthesis of ECM proteins, such as fibronectin and collagens, under conditions of obesity, insulin resistance, and T2D (Jia et al., 2015). The gene discussed is CCN2; the disease is obesity due to melanocortin 4 receptor deficiency.