MMP9 and obesity due to melanocortin 4 receptor deficiency: Additionally, the same research team described that MMP-9and TIMP-1 concentrations were elevated in obese children and adolescents, and thatthe values of these parameters increased even further when obesity was accompaniedby hypertension.12 Moreover, Beloet al.21 reported that genotypesand haplotypes of MMP-9 gene modulate circulating MMP-9 levels in obese children andadoslecentes.