Mental retardation occurs in some cases. The name Treacher Collins is sometimes erroneously hyphenated. Crumpled malformed pinnae which are usually misplaced toward the angle of the mandible, absent external auditory canals, and defective ossicles. Extra ear tags and blind fistulae may exist in the ear lobes and between the tragus and the angle of the mouth. Short and downward sloping palpebral fissures and colobomas of the lower eyelids or irides are the main ocular features.
Supraorbital ridges are hypoplastic.
Obliterated nasofrontal angle, narrow nares, and hypoplastic alar cartilage. The syndrome is familial and is transmitted as an autosomal dominant trait. A variant associated with mental deficiency in which the affected males have no chromosomal abnormalities is transmitted as an autosomal recessive trait.