Autosomal dominant microtia and ocular coloboma: new syndrome or an extension of the oculo-auriculo-vertebral spectrum?

The oculo-auriculo-vertebral (OAV) spectrum is an etiologically heterogeneous condition classically consisting of microtia, hemifacial microsomia, epibulbar dermoids, and vertebral anomalies. Other eye findings described in OAV include upper eyelid colobomas, ptosis, and varying degrees of microphthalmia or even anophthalmia. Iris and/or retinal colobomas have rarely been reported. We describe two familial cases of apparent OAV with ocular colobomas. We postulate that iris and/or retinal colobomas associated with OAV may represent a subgroup within the OAV spectrum with autosomal dominant inheritance, as in the families described herein. Since microtia can result from aberrant migration of neural crest cells into the first and second branchial arches during early embryonic development, and concomitant deficient neural crest migration into the developing eye can lead to ocular coloboma and or iris heterochromia, it may be that the altered gene or genes in our familial cases are involved with regulation of neural crest development.