Thus, high levels of plasma IL6 are correlated with obesity (Fried et al., 1998), type 2 diabetes and even with the prediction of this pathology (Pradhan, 2001), and it decreases with the loss of adipose tissue and body weight (Ziccardi et al., 2002; Esposito et al., 2003). The gene discussed is IL6; the disease is obesity due to melanocortin 4 receptor deficiency.