Furthermore, based on protein–protein interaction network analyses of differentially expressed genes in the AT of children with normal weight or overweight and obesity, Li et al. suggested matrix metalloproteinase 9 (MMP9) and acetyl-CoA carboxylase β (ACACB) as marker genes for childhood obesity [24]. The gene discussed is MMP9; the disease is obesity due to melanocortin 4 receptor deficiency.