Cathepsin K belongs to the family of lysosomal cysteine cathepsins; it is involved in the turnover of ECM proteins in many organs, and contributes to cardiovascular disease (including atherosclerosis and aortic aneurysms), inflammation, and obesity (Lv et al., 2013; Podgorski, 2009). This evidence concerns the gene CTSK and obesity due to melanocortin 4 receptor deficiency.