Familial Treacher-Collins syndrome.

The major congenital malformations of the first and second branchial arch derivatives such as mandibulofacial dysostosis have a genetic basis. Treacher-Collins syndrome is transmitted as an autosomal dominant trait, although many cases occur as spontaneous mutations. The characteristics are hypoplasia of the malar, mandibular and maxillary bones, antimongoloid slanting of the palpebral fissures and a receding chin. The aural findings include malpositioning or maldevelopment of the pinna or external auditory meatus, an atretic bony plate instead of tympanic membrane, or ossicular malformations. Five members of a Hindu family affected by Treacher-Collins syndrome spanning three generations are examined in detail, with special reference to their hearing.