Undifferentiated connective tissue disease (UCTD) is a diagnosis given to patients who do not fulfill current classification criteria for named connective tissue diseases (CTD)—systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), systemic sclerosis (SSc), or Sjögren’s disease—but who nonetheless have clinical signs and symptoms and serological evidence of autoimmune CTDs. In 1980 LeRoy et al. were…
