Treacher Collins syndrome (TCS) is a rare genetic disorder characterized primarily by abnormalities in the development of the head and face. Underdevelopment (hypoplasia) of the cheekbones and related structures (zygomatic bones) as well as the jawbone are common findings. Consequently, patients generally have a distinctive facial appearance. The jaws, ears and eyes are commonly affected, potentially causing respiratory, hearing and vision complications. TCS is a highly variable disorder. Mild cases can go unrecognized and undiagnosed, while severe cases can lead to serious, life-threatening respiratory complications.