Klinefelter's syndrome and rheumatoid arthritis. Report of a case and review of the literature.

Our case report describes a patient with Klinefelter's syndrome (KFS) associated with rheumatoid arthritis (RA). He had active RA in 1985 but his arthritis almost subsided in 1993 without intensive treatments for RA as well as KFS. Recently, the lower levels of testosterone in male RA patients, especially at the active phase has been reported. However, it is still questionable whether hypogonadism is a predisposing factor or just a consequence of disease. Since our case had a mild clinical course, and since the incidence of RA associated with KFS is very rare in comparison with other rheumatic diseases, may suggest that the low levels of testosterone are not a predisposing factor to the activity of RA.