Elevated TGF-β1 levels are detected in the adipose tissue of obese humans and mice, and TGF-β1 inhibition confers protection against obesity (Alessi et al. 2000; Samad et al. 1997; Yadav et al. 2011) (Fig. 1). The gene discussed is TGFB1; the disease is obesity due to melanocortin 4 receptor deficiency.