Undifferentiated Connective Tissue Diseases

**Definition:** Diseases that exhibit signs and symptoms suggestive of a connective tissue disease that do not fulfill clinical or diagnostic criteria for any one defined disease but overlap with criteria of multiple such diseases. Commonly overlapping diseases include systemic autoimmune connective tissue diseases such as RHEUMATOID ARTHRITIS; SYSTEMIC LUPUS ERYTHEMATOSUS; and SYSTEMIC SCLEROSIS.

**Tree numbers:** - C17.300.849 - C20.111.904

**Synonyms:** - Undifferentiated Connective Tissue Disease