DKKl & SOST

The dickkopf protein family interacts with the Wnt signaling pathway and its members are characterized by two conserved cysteine-rich domains. This gene encodes a secreted protein that has low sequence similarity to the dickkopf-3 protein. Multiple alternatively spliced transcript variants encoding distinct isoforms have been found for this gene.

Sclerostin is a secreted glycoprotein with a C-terminal cysteine knot-like (CTCK) domain and sequence similarity to the DAN (differential screening-selected gene aberrative in neuroblastoma) family of bone morphogenetic protein (BMP) antagonists. Loss-of-function mutations in this gene are associated with an autosomal-recessive disorder, sclerosteosis, which causes progressive bone overgrowth. A deletion downstream of this gene, which causes reduced sclerostin expression, is associated with a milder form of the disorder called van Buchem disease.