Treacher Collins syndrome (TCS), which is also known as mandibulofacial dysostosis, is an autosomal dominant condition with variable expressivity.* It is generally characterized by bilaterally symmetric abnormalities of the structures within the first and second branchial arches. Early descriptions are attributed to Berry,10 Treacher Collins,51 and Franceschetti and Klein.41 To date, the physical findings of many hundreds of individuals and families with TCS have been published in the world literature.