INS and obesity due to melanocortin 4 receptor deficiency: The development of obesity is usually the result of a chronic imbalance between energy intake and energy expenditure [5], however, this does not evaluate the metabolic alterations that regulate energy balance, such as the peptide hormone leptin, secreted primarily from white adipose tissue into the bloodstream to bind its receptors in peripheral tissues, inducing gluconeogenesis in the liver and inhibits the release of insulin from pancreatic β cells; it has been proved that insufficient leptin action leads not only to the development of obesity but also increases insulin resistance [6, 7].