On the other hand, OPG might contribute to endothelial dysfunction by blocking the RANKL signalling which is able to activate protective intracellular endothelial pathways such as the nitric oxide synthase pathway and increase the adhesion and migration of inflammatory cells through the endothelium and the activity of metalloproteases [15, 28, 29]. The gene discussed is TNFRSF11B; the disease is endothelial dysfunction.