Colonic RGS9 demonstrated significant overexpression in obesity compared to lean (0.0033 ± 3.9e-004 vs. 0.0012 ± 2.1e-004, respectively; mean difference 0.002142 [95% CI 0.001250–0.003035], Log2FC = 1.50; p < 0.0001) (Fig. 2a). This evidence concerns the gene RGS9 and obesity due to melanocortin 4 receptor deficiency.