FABP4 and obesity due to melanocortin 4 receptor deficiency: To evaluate whether the bioenergetics differences identified in VAT of patients with obesity classes 2 and 3 could have been influenced by the number of adipocytes per mass of VAT or the expression of genes involved in pyruvate, glutamine, and fatty acid metabolism, OB, MPC1, LDHA, SLC2A4, CPT1a, FABP4, GLS1 and SLC1A5 gene expressions were evaluated.