SOX9 is a member of the SOX (SRY-box 9) family of transcription factors involved in the determination of cell fate during embryogenesis. This protein and acts during testis determination, chondrocyte differentiation, and is involved in regulating transcription of the anti-Muellerian hormone (AMH) gene. Loss of this protein leads to campomelic dysplasia, a disorder with skeletal deformities accompanied by male-to-female sex reversals. In adult tissues, the protein has been identified as a stem cell regulator. It is expressed in the nucleus in a wide variety of tissues including the brain, salivary gland, testis, tonsil, thyroid, seminal vesicle, breast, and GI tract, particularly within adult stem and progenitor cells. SOX9 dysregulation has also been implicated in the pathogenesis of various cancers via activation of the WNT pathway. References: Genes & Diseases 2014 1(1):149; J Clin Invest 2016 10.1172/JCI78815; J Cell Biol 2004 166(1):37