Mixed connective tissue disease

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.

It is sometimes equated with the term "Undifferentiated connective tissue disease", ) but some sources specifically reject such assertions of equivalence. The term was introduced by Leroy in 1980.

Clinical features
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: Distinguishing laboratory characteristics are a positive, speckled anti-nuclear antibody and an anti-U1-RNP antibody.
 * joint pain/swelling,
 * malaise,
 * Raynaud phenomenon,
 * Sjögren's syndrome,
 * muscle inflammation, and
 * sclerodactyly (thickening of the skin of the pads of the fingers)

It has been associated with HLA-DR4.

The prognosis for MCTD tends to be better than other autoimmune diseases due to lack of renal disease and response to corticosteroids.