As shown in Fig. 1, irisin levels were significantly higher in normal weight children (8.05 [7.24–8.94]) compared with children with obesity (6.08 [4.68–6.65]) and those with the MS (6.46 [5.74–7.02]) (p < 0.001). This evidence concerns the gene FNDC5 and obesity due to melanocortin 4 receptor deficiency.