A theory on the embryogenesis of oculo-auriculo-vertebral (Goldenhar) syndrome.

Oculo-auriculo-vertebral (OAV) syndrome is made up of anomalies, mainly of first and second branchial arch derivatives. Characteristic features include structural malformations of the external and middle ears, face, and jaw. It has been previously suggested that hemorrhage involving the first and second branchial arches causes hypoplasia and malformation of the face and auricle, but this theory cannot explain the multisystemic and protean manifestations of this disease. The theory set forth describes the cutaneous, facial, vertebral, and systemic anomalies in the OAV spectrum as a result of ectodermal nondisjunction early in development with subsequent mesodermal tethering. A subgroup of OAV may therefore be a disorder of ectodermal nondisjunction involving the otic placode similar to the spectrum of diseases such as occult spinal dysraphism that is associated with the same mechanism in the embryonic neuraxis. This would imply a molecular mechanism involving cell adhesion molecules that unify the two disease processes and explain the multisystem anomalies of the OAV syndrome.