Clarifying the Relationship Between Orbito-Zygomatic and Mandibular Dysmorphology in Treacher Collins Syndrome

This study aims to clarify the relationship between orbito-zygomatic and mandibular dysmorphology as well as their associations with the most frequently observed craniofacial anomalies in patients with Treacher Collins syndrome (TCS).

The authors retrospectively reviewed patients with TCS who presented between 2000 and 2023. Patients were included if they had at least one computed tomography scan performed before skeletal reconstruction along with clinical photographs. Serial scans were used to grade degrees of orbito-zygomatic and mandibular dysmorphology using previously published severity scales.

Ninety hemi-skulls were evaluated among 35 patients at an average age of 5.7±5.6 years. There was a significant positive correlation between the severity of orbito-zygomatic and mandibular hypoplasia (r=0.294, P=0.005). Greater severity of orbito-zygomatic hypoplasia was positively correlated with down-slanting palpebral fissures (r=0.461, P<0.001), ectropion (r=0.381, P<0.001), ptosis (r=0.327, P=0.002), eyelash problems (r=0.268, P=0.011), and eyelid coloboma (r=0.104, P<0.001). Greater severity of mandibular hypoplasia was correlated with intubation or tracheostomy as a neonate (r=0.519, P<0.001), NG tube or gastrotomy (r=0.355, P<0.001), cleft lip and/or palate (r=0.349, P<0.001), and microtia (r=0.304, P=0.004).

The authors found a positive correlation between (1) severity of orbito-zygomatic and mandibular dysmorphology, (2) severity of orbito-zygomatic hypoplasia and the presence of periorbital deficiencies, and (3) severity of mandibular hypoplasia and history of oropharyngeal airway compromise in patients with TCS. Given the morbidity risk and surgical burden associated with these dysmorphologies, early identification of and anticipation for a greater number of aesthetic and functional challenges based on the severity of underlying skeletal deficiencies is critical.