Congenital microcoria: Description of 3 cases in a family.

Congenital microcoria (MCOR) is a rare ocular anomaly characterized by pupil smaller than 2 mm with no response to mydriatic agents. It can present in two forms: autosomal recessive associated with Pierson syndrome and autosomal dominant isolated (associated with a high incidence of myopia and glaucoma). Studies have identified deletions in the 13q32.1 region of chromosome 13 that include the GPR180 gene, involved in smooth muscle cell growth, as the underlying cause. We describe 3 members of a family with deletion of the GPR180 gene on chromosome 13. In all, IOP was normal and gonioscopy showed iridocorneal angle dysgenesis with prominent ciliary processes. MCOR is due to poor development of the iris dilator muscle of genetic cause. Early diagnosis and continuous follow-up for possible complications such as amblyopia, progressive myopia and juvenile glaucoma is essential.