Chromosome 6p25 deletion syndrome: report of a case with optic disc coloboma and review of published ophthalmic findings.

Purpose: The 6p25 deletion syndrome is a rare disorder characterized by Dandy-Walker malformation, congenital heart defects, developmental delay, dysmorphic facial features, and malformations of the anterior segment of the eye with a risk for glaucoma. Here we report a child harboring a cryptic de novo 6p25 deletion, bilateral optic disc coloboma and characteristic anterior segment anomalies. We review reported ophthalmic findings in patients with this syndrome.
Materials and Methods: Retrospective case review of a 4-day-old male with Dandy-Walker malformation and cardiac defects who was referred with a suspected diagnosis of iris coloboma.
Results: The ophthalmic examination showed bilateral corectopia associated with posterior embryotoxon. Fundus examination revealed bilateral optic disc excavation, which was diagnosed as colobomatous because of its configuration and stability over time. Because of the association of posterior embryotoxon with Dandy-Walker malformation, a terminal 6p deletion syndrome was clinically suspected. Array comparative genomic hybridization (CGH) and fluorescence in situ hybridization (FISH) studies revealed a 3.2 Mb deletion at 6p25.2p25.3 including the FOXC1 gene. Neither unaffected parent carried this deletion.
Conclusions: Optic disc colobomas may be found in patients carrying a 6p25 deletion. This has the potential to confound assessment of affected children for glaucoma and intracranial hypertension.