SPP1 and obesity due to melanocortin 4 receptor deficiency: The lack of association of OPN, a molecule deeply involved in the development of obesity-associated insulin resistance as evidenced by previous works23, 29, 31 and the correlations observed in the present study, with the adiponectin/leptin ratio suggest the potential involvement of other factors secreted by the adipose tissue in inflammation and oxidative stress37, 38.