Treacher Collins syndrome (TCS) is characterized by lower eyelid abnormalities, malar hypoplasia, downslanted palpebral fissures, and micro- or retrognathia due to symmetric hypoplasia of the zygomatic bones, maxilla, and mandible. External ear anomalies include absent, small, malformed, and/or posteriorly rotated ears and atresia or stenosis of the external auditory canals. About 40%-50% of individuals have conductive hearing loss attributed most commonly to malformation of the ossicles and hypoplasia of the middle ear cavities. Inner ear structures tend to be normal. Significant respiratory and feeding difficulties can be present in infancy. Other, less common abnormalities include cleft palate and unilateral or bilateral choanal stenosis or atresia. Typically, intellect is normal. [from GeneReviews]