Sox genes comprise a family of genes that are related to the mammalian sex-determining gene SRY. These genes similarly contain sequences that encode for the HMG-box domain, which is responsible for the sequence-specific DNA-binding activity. Sox genes encode putative transcriptional regulators implicated in the decision of cell fates during development and the control of diverse developmental processes. SOX9 plays an important role in the normal skeletal development. It may regulate the expression of other genes involved in chondrogenesis by acting as a transcription factor for these genes.