Early-onset hydroxychloroquine maculopathy: on the importance of genetic work-up

PURPOSE: To report a case of bull's eye maculopathy in a 61-year-old female following short-term hydroxychloroquine (HCQ) exposure. METHODS: This was a retrospective chart review of a single patient case. RESULTS: The patient had normal macular anatomy at HCQ initiation. After less than two years of HCQ therapy, the patient developed subtle interval outer retinal thinning of the parafovea. After four years of therapy, she developed a florid bull's eye pattern maculopathy and HCQ was discontinued. She continued to have indolent progressive vision loss for several years, and multifocal electroretinogram revealed diminished photoreceptor responses. Genetic testing identified a dominant cone-rod dystrophy due to mutation in the CRX gene. CONCLUSION: This patient developed bull's eye maculopathy after limited exposure to HCQ. Genetic testing revealed an underlying cone-rod dystrophy, which likely increased her susceptibility to HCQ toxicity. This case emphasizes the importance of diagnostic work-up for unusually early-onset HCQ maculopathy, which may include genetic testing.