Bilateral Macular Dysplasia in Coffin-Siris Syndrome.

Purpose: To report a case of bilateral macular dysplasia without pigmentary retinopathy in a patient with genetically confirmed Coffin-Siris syndrome (CSS) and a co-existing, heterozygous CNGB1 variant.

Methods: Case report.

Results: A 7-year-old boy who failed his vision screening was referred for retinal consultation after his eye care provider identified bilateral macular deposits. Past medical history included developmental delay, atypical facial features, uteropelvic junction obstruction, koilonychia, and corpus callosum dysgenesis. The patient underwent whole exome sequencing, which revealed a pathogenic variant in the ARID1A gene consistent with a diagnosis of Coffin-Siris syndrome. Genetic testing also revealed a heterozygous, missense variant in the CNGB1 gene of unknown significance. Fundus examination revealed fine hypopigmented lesions in the macula with surrounding retinal pigment epithelial changes in both eyes. Spectral-domain ocular coherence tomography revealed abnormalities of the ellipsoid and interdigitation zones. The patient's best-corrected visual acuity and clinical examination remained stable for a decade since his initial examination, with persistent macular dysplasia and no pigmentary retinopathy.

Conclusions: It is possible that the ocular findings in this case may expand the phenotypes associated with CSS.