FRZB also known as sFRP-3, is a secreted protein containing a domain similar to the putative Wnt-binding region of the frizzled family of transmembrane receptors. FRZB is widely expressed in adult mammalian tissues. In the Xenopus gastrula, FRZB is regulated as a typical Spemann organizer component. FRZB also functions as a competitor for the cell-surface G-protein receptor Frizzled. It is espically important in embryonic development. Defects in FRZB gene can cause female-specific osteoarthritis (OA) susceptibility. FRZB may serve an important role in determining hip shape and may modify the relationship between hip shape and OA.