Mandibular Dysmorphology and Clinical Presentation in Treacher Collins Syndrome.

Introduction: Treacher Collins syndrome is a rare congenital disease characterized by the multiple craniofacial malformations. Although the deformities affecting patients with Treacher Collins syndrome have been well characterized, the effects of these malformations to clinical severity of the syndrome are not well understood.

Objective: To determine the association of specific Treacher Collins mandibular malformations with clinical severity.

Design: A retrospective radiographic observational study.

Setting: Study conducted at a single institution, a quaternary craniofacial care center.

Patients: 54 patients with Treacher Collins syndrome.

Interventions: Computed tomography (CT), clinical photographs and medical history were included in this analysis. Mandibles were isolated from CT data and reconstructed in three dimensions using Mimics software. Cephalometric measurements were performed on CT data. Clinical severity was determined by Teber and Vincent scores. Association of craniofacial dysmorphology to clinical severity was determined by Spearman rank coefficient.

Main outcome measures: The main results obtained were the measurements of the mandibles and the quantification of the malformations of the evaluated patients.

Results: Among the most frequent findings in the sample are hypoplasia of the zygomatic complex, descending palpebral cleft and mandibular hypoplasia. Patients with a lower ramus/corpus ratio had a higher (more severe) Teber and Vincent classification.

Conclusion: Patients with the most compromised mandible are also the patients with the highest number of malformations, thus, the most severe patients.