Subdividing people with obesity into MetsO and MHO, a positive correlation was also detected between MMP-1 and BMI values in both MetsO (r = 0.25, p = 0.03, Fig. 1e) and MHO (r = 0.28, p = 0.03, Fig. 1d). This evidence concerns the gene MMP1 and obesity due to melanocortin 4 receptor deficiency.