Mimecan induces ectopic bone formation in conjunction with transforming growth factor beta. Mimecan is a small proteoglycan which contains tandem leucine-rich repeats. Mimecan is encoded by the OGN gene, a member of the small leucine-rich proteoglycan (SLRP) family of proteins. Mimecan induces ectopic bone formation in conjunction with transforming growth factor beta (TGF-beta-1 or TGF-beta-2) and may regulate osteoblast differentiation. High expression of mimecan protein may be associated with elevated heart left ventricular mass. Alternative splicing results in multiple transcript variants of mimecan.