Mixed Connective Tissue Disease (MCTD)

AiArthritis defines Mixed Connective Tissue Disease as:


Mixed connective tissue disease (MCTD) is a rare autoimmune condition characterized by the presence of the anti-U1-ribonucleoprotein antibody. It falls within the category of rheumatic "overlap syndromes," which refers to patients displaying features of more than one classic inflammatory rheumatic disease, including systemic lupus erythematosus, polymyositis, scleroderma, and rheumatoid arthritis. MCTD is distinguished by the presence of anti-RNP antibodies.

Symptoms

Symptoms of AiArthritis Diseases Regardless of Diagnosis

Common in All AiArthritis Diseases



  • Periods of worsening symptoms are called flares. A flare can last for hours, days, weeks, or months.
  • Condition improves with activity and exercise and worsens with rest.
  • When inflammation is left uncontrolled due to lack of proper treatment, comorbidities can develop. 70% of patients with chronic, lifelong disease will develop comorbidities, including dual or triple diagnoses.
  • Autoimmune diseases run in families. If anyone in your immediate family (parents, siblings) or extended family (aunts, uncles, grandparents) have been diagnosed with ANY autoimmune disease, there is the possibility of genetic predisposition.

 “Auto” Symptoms






  • Severe fatigue or exhaustion that may not be helped by caffeine/stimulants and can happen even after a long period of rest.
  • “Brain fog” - or periods of time where thinking gets clouded and it becomes difficult to concentrate.
  • Flu-like symptoms, without having the flu- nausea, muscle weakness, and general malaise.
  • Fever, typically low grade in autoimmune and higher grade in autoinflammatory (% strongly varies per disease).


Reference: Early Symptoms of AiArthritis Study, AiArthritis, 2019.


View Early Symptoms Study

Inflammatory Arthritis Symptoms


  • Severe stiffness in one or more joints, especially in the morning or after sitting for long periods of time. 
  • Episodes of joint pain that may last for hours, days, or even weeks, that can appear and disappear suddenly. Often described as “jumping pain” into different locations.


Typically the joint pain will coincide with one or more “Auto” symptoms and start and stop suddenly - for no apparent reason (which is called a "flare").  Some people will experience all of the above symptoms, others only a few.  If you have any of the arthritis features, and at least one of the “Auto” features, please consult your physician about a referral to a rheumatologist.


Symptoms Often Associated with Mixed Connective Tissue Disease:

  • Symptoms of Reynaud syndrome
  • Difficulty swallowing 
  • Heartburn 
  • Shortness of breath 
  • Hair loss
  • Lungs involvement
  • Sjogren’s syndrome may develop 
  • Overtime, people may develop symptoms that are more typical of lupus or systemic sclerosis 
  • Lupus-like skin inflammation in sun-exposed areas


What fellow patients want you to know

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More About Mixed Connective Tissue Disease (MCTD)

Diagnosing Mixed Connective Tissue Disease (MCTD)

There’s no single definitive test that can confirm a mixed connective tissue disease (MCTD) diagnosis, so rheumatologists look at a combination of physical exam, blood tests, and family history of autoimmune disease. The blood tests that are specifically looked at are conducted to detect the presence anti-U1-ribonucleoprotein (anti-U1-RNP) antibodies, which is a hallmark laboratory finding in MCTD and antinuclear antibodies (ANA) which is looked at in many autoimmune and autoinflammatory diseases. Overlapping of symptoms with lupus, systemic sclerosis, and polymyositis are also often found in those with MCTD.


There is a diagnostic criteria called Alarcon-Segovia that may be used. These criteria require a high titer of positive anti-U1-RNP (over 1 per 1600) and three or more of the following clinical manifestations: Raynaud phenomenon, hand edema, synovitis, histologically proven myositis, and acrosclerosis.

Interesting Facts about this Disease

  • 80% of patients with MCTD are women
  • It is very likely that MCTD develops into SLE (Lupus) or Scleroderma (Systemic Sclerosis)
  • MCTD is often referred to as an "overlap syndrome"

Other Resources

In an effort to ensure this page has the most accurate and up-to-date information, this page is currently awaiting medical review. Some information is subject to change.


Page Last Updated: 9/1/2023

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