Recent studies in rodents unveil the physiological role of spexin in obesity and diabetes (Walewski et al., 2014; Gu et al., 2015), which is supported by the clinical observations that circulating level of spexin is negatively correlated with blood glucose in type 2 diabetes mellitus (T2DM) patients (Gu et al., 2015) and body weight in obese children (Kumar et al., 2016). This evidence concerns the gene SPX and obesity due to melanocortin 4 receptor deficiency.