PM20D1 and obesity due to melanocortin 4 receptor deficiency: Peptidase M20 domain containing 1 (PM20D1) and Slit2 are two newly identified batokines that improves glucose homeostasis as well as regulate thermogenesis which might be used for the treatment of obesity and obesity associated metabolic disorders (Long et al., 2016; Svensson et al., 2016).