TNFSF11 and obesity due to melanocortin 4 receptor deficiency: Interestingly, there are also some reports, which link specific variants of the OPG [OPG, rs3736228 (AG/AA) variant] and RANK [RANK, rs11664594 (A/T) variant] genes to an increased risk of obesity, which may imply a potential involvement of the OPG-RANKL-RANK axis in the pathogenesis of obesity, but requires validation in independent cohorts of obese individuals [33, 34].