TNFRSF11B (Tumor Necrosis Factor Receptor Superfamily Member 11B): TNFRSF11B is a protein, also known as osteoprotegerin, that plays a key role in bone metabolism. It acts as a decoy receptor for RANKL, helping to inhibit osteoclast formation and prevent bone resorption. TNFRSF11B is essential for maintaining bone density and strength, and changes in its function are associated with osteoporosis and other bone disorders.