Studies have shown that its up-regulation is significantly associated with human obesity, and mice with biallelic knockout mutations of IRX3 knockout did not significantly reduce their viability after birth and can significantly enhance basal metabolism, reduce fat content, and ultimately reduce body weight, suggesting that IRX3 is a major gene that controls body mass and composition in human and mouse [65,66]. The gene discussed is IRX3; the disease is obesity due to melanocortin 4 receptor deficiency.