A new type of maxillofacial dysostosis, inherited as an X-linked or autosomal recessive trait.

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 characteristics are more typical of maxillofacial than of mandibulofacial dysostosis. These cases most likely represent a new type of maxillofacial dysostosis inherited as an X-linked or autosomal recessive trait.