Rheumatic diseases and Klinefelter's syndrome

The article summarizes reports on the concurrence of Klinefelter's syndrome (KS) with inflammatory rheumatic diseases, rheumatoid arthritis (RA), juvenile idiopathic arthritis, psoriatic arthritis, polymyositis/dermatomyositis, systemic lupus erythematosus, systemic sclerosis, mixed connective tissue disease, the antiphospholipid syndrome, and ankylosing spondylitis. These include two case reports of patients with KS concurrently associated with RA or antisynthetase syndrome, respectively, previously reported by the author and his coworkers. Attention is paid to the pathogenesis and the course of the disease in patients with KS. The importance of early diagnosis of the syndrome, when occurring simultaneously with other diseases of connective tissue, is emphasized.