SOX9 and Campomelic Dysplasia and Sex Reversal

Abstract Campomelic dysplasia (also known as camptomelic dysplasia) (CMD) is a rare, usually lethal skeletal dysplasia. Unlike other forms of skeletal dysplasia, it is frequently associated with XY sex reversal. The gene for this condition, SOX9, was identified in 1994. As suggested by the phenotype in CMD, SOX9 is an important gene, not only in the sex determination pathway but also in chondrogenesis. In this chapter, I discuss SOX9 and its role in both the sex determination pathway and the cartilage and collagen pathway. The clinical and radiological features of CMD are described, including the phenotype and complications in survivors with this condition.