These mice exhibited typical metabolic characteristics associated with obesity, including significant increases in body weight (Figures 1A and 1B), adipose tissue mass (Figure 1C), blood glucose levels (Figures 1D and S2A), fasting serum leptin level (Figure S2B), and fasting serum insulin level (Figure 1E). This evidence concerns the gene LEP and obesity due to melanocortin 4 receptor deficiency.