In medicine, mixed connective tissue disease (also known as Sharp's syndrome), commonly abbreviated as MCTD, is an autoimmune disease in which the body's defense system attacks itself. It was characterized in 1972, and the term was introduced by Leroy in 1980.
It is sometimes said to be the same as undifferentiated connective tissue disease, but other experts specifically reject this idea.
Signs and symptoms MCTD combines features of scleroderma, myositis, systemic lupus erythematosus, and rheumatoid arthritis (with some sources adding polymyositis, dermatomyositis, and inclusion body myositis) and is thus considered an overlap syndrome.
MCTD commonly causes:
muscle inflammation, and
sclerodactyly (thickening of the skin of the pads of the fingers)