Causes Make an Appointment Refer a Patient Ask a Question Reviewed by Barbara Goldstein, MD (February 01, 2016) 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. 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. Symptoms Clinical Trials For more than 100 years, National Jewish Health has been committed to finding new treatments and cures for diseases. Search our clinical trials.