**Core Concept**
Treacher-Collins syndrome is a rare genetic disorder characterized by deformities of the ears, eyes, cheekbones, and chin. It is caused by mutations in the TCOF1 gene, which encodes a protein essential for the development of craniofacial structures.

**Why the Correct Answer is Right**
Treacher-Collins syndrome is associated with underdeveloped facial bones, including the maxilla, mandible, and zygoma. This leads to characteristic features such as micrognathia (small jaw), mandibular hypoplasia, and lower eyelid coloboma. The syndrome also affects the ears, often resulting in microtia (small ears) or anotia (absence of ears). The TCOF1 protein plays a crucial role in the development of these craniofacial structures during embryogenesis.

**Why Each Wrong Option is Incorrect**
**Option A:** Not a feature of Treacher-Collins syndrome. While Treacher-Collins syndrome does involve craniofacial abnormalities, it does not typically present with intellectual disability or developmental delay.

**Option B:** Not a feature of Treacher-Collins syndrome. However, some individuals with Treacher-Collins syndrome may experience hearing loss due to the abnormalities in the middle ear.

**Option C:** Not a feature of Treacher-Collins syndrome. While Treacher-Collins syndrome does involve craniofacial abnormalities, it does not typically present with cleft palate.

**Option D:** Not a feature of Treacher-Collins syndrome. However, some individuals with Treacher-Collins syndrome may experience respiratory difficulties due to micrognathia and airway obstruction.

**Clinical Pearl / High-Yield Fact**
Treacher-Collins syndrome is an autosomal dominant disorder, meaning that a single copy of the mutated TCOF1 gene is sufficient to cause the condition. This is in contrast to some other craniofacial disorders, which may be caused by mutations in multiple genes or have a more complex inheritance pattern.

**Correct Answer:** A.