Treacher Collins syndrome: abnormal first branchial arch development giving rise to malar and mandibular hypoplasia with external ear malformations. Dysmorphology is the study of malformations arising from abnormal embryogenesis. Recognition of patterns of multiple congenital malformations may allow inferences to be made about the timing, mechanism, and aetiology of structural defects. Animal r...

Two brothers with congenital conductive hearing loss and phenotypic characteristics of maxillofacial dysostosis are described. In the oldest boy a malformed ossicular chain was present and the conductive hearing loss was improved by a malleo-vestibulo-pexy, with post-operative hearing gain of approximately 30 dB. Although superficially similar to Treacher Collins syndrome, the facial characteri...