What are the genetic changes related to CHOPS syndrome ?
CHOPS syndrome is caused by mutations in the AFF4 gene. This gene provides instructions for making part of a protein complex called the super elongation complex (SEC). During embryonic development, the SEC is involved in an activity called transcription, which is the first step in the production of proteins from genes. By re-starting the transcription of certain genes after pauses that normally occur during the process, the SEC helps ensure that development proceeds appropriately before birth.  Mutations in the AFF4 gene are thought to result in an AFF4 protein that is not broken down when it is no longer needed, so more AFF4 protein is available than usual. The excess AFF4 protein interferes with normal pauses in transcription. This dysregulation of transcription leads to problems in the development of multiple organs and tissues, resulting in the signs and symptoms of CHOPS syndrome.