With regard to the role of NRG-4 as an endocrine factor, the plasma levels of NRG-4 and the possible association with obesity, type 2 diabetes and cardiovascular diseases-related to metabolic syndrome have been examined in humans (Dai et al., 2015; Cai et al., 2016; Jiang et al., 2016; Kang et al., 2016; Yan et al., 2017, 2018; Tian et al., 2019; Wang R et al., 2019). This evidence concerns the gene NRG4 and obesity due to melanocortin 4 receptor deficiency.