What causes Treacher Collins syndrome ?
What causes Treacher Collins syndrome? Treacher Collins syndrome (TCS) is caused by changes (mutations) in any of several genes: TCOF1 (in over 80% of cases), POLR1C, or POLR1D. In a few cases, the genetic cause of the condition is unknown. These genes appear to play important roles in the early development of bones and other tissues of the face. They are involved in making proteins that help make ribosomal RNA (rRNA). rRNA is a chemical needed to make new proteins that are necessary for normal function and survival of cells. Mutations in these genes can reduce the production of rRNA, which may cause cells involved in the development of facial bones and tissues to die early. This premature cell death may lead to the signs and symptoms of TCS. It is still unclear why the effects of these mutations are generally limited to facial development.