What is characteristic of Treacher Collins Syndrome?

Treacher Collins Syndrome is primarily characterized by specific craniofacial anomalies, which include micrognathia (a small jaw) and various external ear anomalies. These features are significant manifestations of the condition and result due to disruptions in the development of the first and second pharyngeal arches during embryogenesis.

Individuals with Treacher Collins Syndrome often exhibit additional traits such as zygomatic hypoplasia (underdeveloped cheekbones) and a down-slanting of the palpebral fissures (the openings between the eyelids). While hearing loss is common in these patients, it does not occur in every case, so it would not be accurate to state that it is present in 100% of cases. Additionally, renal abnormalities are not a typical feature associated with Treacher Collins Syndrome, nor is severe intellectual disability, as cognitive function can vary widely and many individuals may have normal intelligence levels. Thus, the defining characteristics of micrognathia and external ear anomalies make this choice the most accurate representation of Treacher Collins Syndrome.