INS and obesity due to melanocortin 4 receptor deficiency: Retinoic acid receptor responder 2 (RARRES2), also known as chemerin, is an important adipokine in obesity, inflammation, and cardiovascular disease. Previous studies have reported that chemerin could promote angiogenesis and ROS production and decrease insulin signaling and nitric oxide production in vascular endothelial cells (Bozaoglu, et al. 2010; Neves, et al. 2018; Ferland, et al. 2020).