In contrast, it has also been reported that serum myonectin levels are elevated in obesity, MS, and T2D [20,21,22,23], and a positive association was seen between circulating concentrations of myonectin and fat mass, total FFA, TG, and IR while there was a negative association with high-density lipoprotein cholesterol (HDL-C) [23]. Here, ERFE is linked to obesity due to melanocortin 4 receptor deficiency.