Membrane type 1 matrix metalloproteinase (MT1-MMP; MMP-14) is a zinc-dependent type I transmembrane endopeptidase with very important roles both in physiological (epithelial morphogenesis, skeletal development, and wound healing) and pathological (angiogenesis, arthritis, tumor growth, and metastasis, obesity, inflammation, and atherosclerosis) events. This evidence concerns the gene MMP14 and obesity due to melanocortin 4 receptor deficiency.