Nrg4 is a newly identified adipokine and play a role in obesity, diabetes, non-alcoholic fatty liver disease (NAFLD), and CVD in human subjects (Wang et al., 2014; Dai et al., 2015; Jiang et al., 2016; Chen et al., 2017; Yan et al., 2019). Here, NRG4 is linked to obesity due to melanocortin 4 receptor deficiency.