In addition, Npy1rrfb male mice fed with an HFD display increased body weight, visceral adipose tissue and blood glucose levels, and food and calories intake as compared to control Npy1r2lox mice, suggesting that, in male mice, inactivation of the Npy1r gene increases susceptibility to diet-induced obesity and glucose intolerance, which may be indexes of metabolic syndrome [43]. The gene discussed is NPY1R; the disease is obesity due to melanocortin 4 receptor deficiency.