Furthermore, our findings that Tas2r138 mRNA is upregulated in high-fat diet-induced obesity in mice [29] and that TAS2R38 mRNA and protein are upregulated in the colon of obese/overweight subjects [24] suggest that intraluminal changes in obesity affect these receptors’ expression. The gene discussed is TAS2R38; the disease is obesity due to melanocortin 4 receptor deficiency.