Unexpected Etiology in a Case of Bilateral Maculopathy

A 74-year-old woman with a history of rheumatoid arthritis using hydroxychloroquine presented with gradually progressive decreased vision in both eyes and was found to have a bilateral maculopathy. Initial genetic testing was negative, and after discussing the low likelihood of her severe findings being secondary to her relatively low hydroxychloroquine exposure, the possibility of an autoimmune retinopathy was entertained. Updated data on the genetic testing reclassified one of her mutations in HGSNAT as pathogenic. This case highlights the value of genetic testing and the need to keep a high index of suspicion even after initial negative results, given the fact that our knowledge of mutations leading to retinal degeneration is constantly evolving.