Mixed connective tissue disease is a rare autoimmune disorder that has three other connective tissue diseases (systemic lupus erythematosus, scleroderma and polymyositis).
Mixed connective tissue disease (MCTD) is a rare autoimmune disorder. An autoimmune disorder is one in which your immune system mistakenly views your body’s own tissues as “invaders” and attacks them.
Mixed connective tissue disease has features of three other connective tissue diseases:
About 25% of people with a connective tissue disease (such as dermatomyositis, rheumatoid arthritis, Sjogren’s syndrome, and the three diseases listed above), develop another connective tissue disease over the course of several years. This is known as an “overlap syndrome.”
MCTD is a rare disease, occurring most often in women and people assigned female at birth in their 20s and 30s. Children can also be diagnosed with the disease.
The causes of MCTD aren’t known. It’s not directly inherited, although some research shows that the disease may occur more often in people with a biological family history of connective tissue disease. Exposure to certain viruses or chemicals such as polyvinyl chloride and silica are other possible causes.
In the beginning stages, people who have MCTD have symptoms similar to those with other connective tissue disorders, including:
Less common early symptoms may include:
The “classic” symptoms of MCTD are:
A diagnosis can be difficult to make because the three conditions (SLE, scleroderma and polymyositis) that can be seen in MCTD usually occur one after the other over a long period of time, rather than at the same time. It may take several years to make an accurate diagnosis of MCTD.
There are four features that point to MCTD rather than another connective tissue disorder:
Treatment for MCTD must be tailored to each individual person, depending on the organs that are affected and how severe their condition is. Some people may need treatment only during flare-ups, while others may require constant care.
Treatment considerations include:
As the causes of MCTD aren’t known, there isn’t a way of preventing the disease.
As MCTD is composed of a number of connective tissue disorders, there are many different possible outcomes, depending on the organs affected, the degree of inflammation and how quickly the disease progresses. With proper treatment, 80% of people survive at least 10 years after diagnosis.
Last reviewed by a Cleveland Clinic medical professional on 05/26/2016.
Learn more about our editorial process.