RARRES2 and obesity due to melanocortin 4 receptor deficiency: The expression level of the TNF-α gene was positively correlated with the expression level of the RARRES2 gene in the GO in patients with T2DM (with grade I and II obesity) (r = 0.66, p < 0.05 and r = 0.67, p < 0.05, respectively) (Fig. 1f, g).