Mixed connective tissue disease presenting with progressive scleroderma symptoms in a 10-year-old girl.

Mixed connective tissue disease (MCTD) is a systemic inflammatory disease affecting connective tissue with the underlying autoimmunological mechanism. The core of MCTD is an appearance of symptoms of several other inflammatory diseases of connective tissue - systemic lupus erythematosus, systemic scleroderma, poly- or dermatomyositis, rheumatoid arthritis at the same time, accompanied by a high level of anti-ribonucleoprotein antibodies (anti-U1RNP). The disease was described more than 40 years ago by Sharp et al.