title: A cephalometric analysis of maxillary and mandibular parameters in Treacher Collins syndrome.
abstract: BACKGROUND
  Treacher Collins syndrome is an autosomal dominant condition of varying severity, affecting the tissues of the first and second branchial arches. The aim of this article is to present a cephalometric analysis of the craniofacial skeleton in Treacher Collins syndrome and provide an age- and sex-matched comparison as a standard control sample.
  
  
  METHODS
  Twenty-four Treacher Collins syndrome patients (11 male patients and 13 female patients; mean age, 17.99 +/- 1.96 years) underwent cephalometric studies, including orthopantomography and lateral and anteroposterior cephalography, as part of their preparation for bimaxillary surgery. Cephalometric parameters assessing the relationships of the skull base, maxilla, and mandible were analyzed and compared with age- and sex-matched control data (mean age, 17.75 +/- 1.95 years).
  
  
  RESULTS
  Cephalometric analysis before orthognathic surgery documented that the Treacher Collins syndrome mandible and midface are expectedly short in the anteroposterior plane; however, the ratio of maxillomandibular deficiency is particularly significant in the female patient. The mandibular plane angle is obtuse, affecting female patients in particular, in whom there is also a posteriorly placed chin point. Affected individuals have a high antegonial notch height. Although the parameters of anterior lower facial height proportion in control and syndrome individuals are similar, posterior face height in Treacher Collins syndrome is reduced.
  
  
  CONCLUSIONS
  This study quantifies the cephalometric dysmorphology of patients with Treacher Collins syndrome and compares it to that of age-matched controls. These cephalometric characteristics have clinical significance in Treacher Collins syndrome and in the planning of bimaxillary advancement and genioplasty in syndrome patients.
authors.affiliation: Toronto, Ontario, Canada From the Divisions of Plastic Surgery and Orthodontics, The Hospital for Sick Children, Center for Craniofacial Care and Research.
authors.forename: David K
authors.initials: DK
authors.lastname: Chong
authors.forename: Dylan J
authors.initials: DJ
authors.lastname: Murray
authors.forename: Jonathan A
authors.initials: JA
authors.lastname: Britto
authors.forename: Brian
authors.initials: B
authors.lastname: Tompson
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Forrest
authors.forename: John H
authors.initials: JH
authors.lastname: Phillips
mesh_terms: D000293:Adolescent; D000328:Adult; D002508:Cephalometry; D005260:Female; D006801:Humans; D008297:Male; D008334:Mandible / Q000000981:diagnostic imaging*; D008342:Mandibulofacial Dysostosis / Q000000981:diagnostic imaging* / Q000601:surgery; D008437:Maxilla / Q000000981:diagnostic imaging*; D011859:Radiography; D019291:Skull Base / Q000000981:diagnostic imaging