Genetics of Rheumatoid Arthritis

This study attempts to identify the genes responsible for rheumatoid arthritis (RA), or inflammation of the joints. It is known that genes play an important role in RA, but their number and significance have not been determined. RA tends to run in families. This study will examine the DNA (hereditary material) of patients with RA and their family members to try to determine which chromosomes(s) contain the genes responsible for the disease. Patients with rheumatoid arthritis and their family members may be eligible for this study. Participants with RA who have a brother or sister with RA will undergo the following procedures: * Review of their medical records * Medical history * Examination of the joints * Hand X-rays * Blood tests Participants who 1) do not have RA but who have a relative with the disease, or 2) have RA and a relative other than a brother or sister who has the disease will provide a blood sample or a buccal (cheek) cell sample. Cheek cells are obtained by swishing a small amount of mouthwash in the mouth or by lightly bushing the inside of the cheek with a swab or brush. The samples will be tested for rheumatoid factor, DNA studies, and HLA type (a blood type found on white blood cells). Certain HLA types have been associated with an increased risk or severity of RA.