Familial Mediterranean fever (FMF) is a rare disease that causes repeated bouts of fever and accumulations of fluid in the body, causing pain in the joints, abdomen, chest, and other sites. There is no known cure for the disease, but many patients have a decrease in the number of attacks with a drug called colchicine. Some patients, however, do not experience enough relief with colchicine or have problematic side effects, making its use difficult or impossible. At present, there is no known therapy for such patients. Familial Mediterranean fever is caused by abnormalities in a gene that controls the action of a chemical involved in inflammation called interleukin-1.