Genotype-Phenotype Study of Patients With Plaquenil -Induced Retinal Toxicity, With Evaluation of the ABCA4 Gene

Background: \- Plaquenil (hydroxychloroquine) is an anti-inflammatory drug that is used to treat some autoimmune diseases such as lupus and rheumatoid arthritis. This drug can damage the retina by causing a condition called plaquenil-induced retinal toxicity, which may lead to vision loss. However, most people taking plaquenil do not develop this problem. Researchers are interested in studying whether differences in a person s genes explain why some people develop plaquenil-induced retinal toxicity while others do not. Objectives: \- To investigate possible correlations between certain genes or genetic mutations and plaquenil-induced retinal toxicity. Eligibility: * Individuals at least 18 years of age who have previously used plaquenil. * Both individuals who have and have not developed plaquenil-induced retinal toxicity will be eligible for this study. Design: * The study requires one or two visits to the National Eye Institute or an outpatient study clinic over a maximum 2-year period. * Participants will provide a personal and family medical history, and will have a full eye examination. * Participants will also provide blood samples for testing. * No treatment will be provided as part of this protocol.