What are the genetic changes related to isolated Pierre Robin sequence ?
Changes in the DNA near the SOX9 gene are the most common genetic cause of isolated Pierre Robin sequence. It is likely that changes in other genes, some of which have not been identified, also cause isolated Pierre Robin sequence.  The SOX9 gene provides instructions for making a protein that plays a critical role in the formation of many different tissues and organs during embryonic development. The SOX9 protein regulates the activity of other genes, especially those that are important for development of the skeleton, including the mandible.  The genetic changes associated with isolated Pierre Robin sequence occur near the SOX9 gene. These abnormalities are thought to disrupt regions of DNA called enhancers that normally regulate the activity of the SOX9 gene, reducing SOX9 gene activity. As a result, the SOX9 protein cannot properly control the genes essential for normal development of the lower jaw, causing micrognathia, and consequently, glossoptosis and cleft palate.