People of all races and ethnic backgrounds may develop undifferentiated connective tissue disease. It occurs more commonly in women and rarely occurs in children. Typically UCTD begins when people are between the ages of 30 and 55 years old.
Although the cause of UCTD is not known, we do know that UCTD is an autoimmune disease. The abnormal immune response may lead to inflammation and damage of the various organs that are involved.