RecruitingDeciphering the Genetic Architecture of Autoimmune DiseasesBackground: Autoimmune diseases can be caused by genes people inherit from their parents. The gene changes that cause these diseases have been well studied in people with European and Asian ancestors. But some diseases behave differently in people who are native to North and South America. Researchers want to know more about the gene changes and other factors that may cause autoimmune diseases among these people. This project will be based in Peru. Objective: To study how gene changes can lead to autoimmune diseases in people native to Peru. Eligibility: People aged 18 years and older with an autoimmune disease. These may include systemic lupus erythematosus; Sjogren disease; scleroderma; rheumatoid arthritis; seronegative spondylo-arthropathies; and systemic vasculitis. Family members and healthy volunteers are also needed. Design: Participants will have 2 clinic visits; these will be 2 weeks apart. The clinics will be in Lima, Iquitos, and other sites in Peru. Visit 1: Participants will have a physical exam. They will answer questions about their health risks and habits. They will provide blood and urine samples. Visit 2: Participants will provide a second blood sample and a stool sample. They will talk about the results of their first clinical exam with researchers. The cost of travel to and from the clinics will be provided. Participants will get $30 per visit and a snack.