Blau syndrome is characterized by familial granulomatous arthritis, iritis, and skin granulomas, comprising an autosomal dominantly inherited syndrome that overlaps both sarcoidosis and granuloma annulare. Restated, Blau syndrome is a rare autosomal dominant disorder characterized by granulomatous polyarthritis, panuveitis, cranial neuropathies, and exanthema. Camptodactyly is another feature, and Crohn's disease occurs in 30%. It is associated with mutations in the NOD2 gene.