Treacher Collins Syndrome

**Semantic type:** Disease or Syndrome

**Definition:** A rare autosomal dominant syndrome caused by mutations in the TCOF1 gene. Its characteristics include underdevelopment of the facial bones, small jaw and chin, absent or small ears, defects in the middle ear resulting in hearing loss, and downward sloping palpebral fissures.

**Synonyms:** - Mandibulofacial Dysostosis