Overlap syndromes

Refers to a group of conditions that have clinical features of, and meet classification criteria for, more than one well-characterized rheumatic disease.

The spectrum of overlap syndromes includes mixed connective tissue disease (MCTD); antisynthetase syndrome; and polymyositis/scleroderma (PM/Scl) overlap syndrome.

MCTD is a distinct clinical entity characterized by overlapping features of systemic lupus erythematosus, scleroderma, myositis, and rheumatoid arthritis in the setting of a high titer of autoantibodies to U1 ribonucleoprotein.

Antisynthetase syndromes form a distinct group characterized by antibodies directed against various aminoacyl-tRNA synthetase enzymes with overlapping clinical features of myositis, arthritis, and interstitial lung disease.

PM/Scl syndrome is characterized by overlapping features of scleroderma and polymyositis, PM/Scl antibody, Raynaud phenomenon, tendon inflammation, and interstitial lung disease.

Treatment of overlap syndromes is tailored to the active clinical manifestations and ranges from supportive therapy to cytotoxic immunosuppressive regimens.

"Overlap syndromes" refers to a diverse group of conditions that have clinical features of, and meet classification criteria for, more than 1 well-characterized rheumatic disease. They usually present subacutely with clinical manifestations that can include different organ systems. The pattern of organ involvement reflects the characteristic features of the well-defined rheumatic diseases occurring together.