IFI6 and obesity due to melanocortin 4 receptor deficiency: Patients under 65 years old showed a higher expression of TFRC (p = 0.002), CCL5 (p < 0.001) and IFI6 (p = 0.006), and those with obesity (BMI ≥ 30) presented higher expression of OAS1 (p = 0.008) and TGFB1 (p = 0.008).