(Table 1) Several studies have shown that serum Nrg4 values were significantly elevated in patients with type 2 diabetes mellitus (T2DM) compared to healthy controls and were positively correlated with serum glucose levels (Kang et al., 2016; Chen et al., 2017b; Kocak et al., 2019), while Zhang et al. (Zhang et al., 2017) suggested that Nrg4 levels were significantly decreased in newly diagnosed T2DM. This evidence concerns the gene NRG4 and diabetes mellitus.