Mixed connective tissue disease

Mixed connective tissue disease (MCTD) is a type of connective tissue disease. With regards to clinical and imaging features, it can have significant overlap with other connective tissue diseases such as systemic lupus erythematosus and scleroderma 1. It is therefore classified as a type of overlap syndrome and at times it even comes under debate as to whether MCTD should exist as a distinct entity 7.


Mixed connective tissue disease is a rare autoimmune condition and is often defined by the presence of a ribonuclease-sensitive extractable nuclear antigen.


A prerequisite for the diagnosis of mixed connective tissue disease is the presence in the serum of high titres of antibodies against uridine-rich RNA-small nuclear ribonucleoprotein (snRNP) - anti-U1-RNP antibodies 10

The presence of anti-U1-70 kd is considered a characteristic feature.

Organ spectrum

MCTD can affect various organ systems, with pulmonary 6 and musculoskeletal 4-5 being two of the key systems affected. As such these are best discussed under separate headings:

History and etymology

It was thought to have been first described by Gordon C Sharp and colleagues in 1972.

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Article information

rID: 16931
Tag: cases
Synonyms or Alternate Spellings:
  • Mixed connective tissue disease (MCTD)
  • MCTD
  • Sharp syndrome
  • Sharp's syndrome

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