In addition, although an observational cross-sectional study did not show an association between circulating RANKL and peripheral artery disease in T2DM patients [80], the same authors demonstrated that circulating RANKL, but not circulating OPG, was associated with the progression of lower limb arterial calcification in a prospective observational study [81]. The gene discussed is TNFRSF11B; the disease is type 2 diabetes mellitus.