Atypical presentation of Oguchi disease with severe cystoid macular edema and compound heterozygous SAG pathogenic variants

A 35-year-old male presented with nyctalopia and progressive central vision loss. Evaluation revealed attenuated retinal vessels, peripheral pigmentary changes, and severe CME bilaterally. Despite treatment with carbonic anhydrase inhibitors and NSAIDS, CME persisted. Initial genetic testing identified a heterozygous pathogenic SAG variant (p.Arg193*), raising suspicion for autosomal dominant RP. However, advanced long-read sequencing revealed a second pathogenic intronic SAG variant (c.-29+3A>G) in trans with the initial variant, confirming a diagnosis of autosomal recessive Oguchi disease.