Sclerostin, also known as SOST, is a member of the Cerberus/DAN family of BMP antagonists. SOST is asecreted glycoprotein with a C-terminal cysteine knot-like (CTCK) domain. It shows sequence similarity to the DAN (differential screening-selected gene aberrative in neuroblastoma) family of bone morphogenetic protein (BMP) antagonists. SOST is produced by the osteocyte and has anti-anabolic effects on bone formation. It is a negative regulator of bone growth that acts through inhibition of Wnt signaling and bone formation.