IFNG and obesity due to melanocortin 4 receptor deficiency: This is shown by the evidence that (1) enrichment of TNF-α-producing and IFN-γ-producing T cells compared with PB is not a specific feature of obesity, but it occurs in lean VAT too; and (2) a shortage of Th1, Tc1 and Tc17 cells is evident in obese VAT compared with the leanness condition.