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

Camptodactyly

Camptodactyly is a medical condition involving fixed flexion deformity of the interphalangeal joints of the little finger. This involves permanent flexure of one or more phalanges...

 is another feature, and Crohn's disease

Crohn's disease

Crohn's disease, also known as regional enteritis, is a type of inflammatory bowel disease that may affect any part of the gastrointestinal tract from mouth to anus, causing a wide variety of symptoms...

 occurs in 30%.

It is associated with mutations in the NOD2

NOD2

Nucleotide-binding oligomerization domain-containing protein 2 also known as caspase recruitment domain-containing protein 15 or inflammatory bowel disease protein 1 is a protein that in humans is encoded by the NOD2 gene located on chromosome 16. NOD2 plays an important role in the immune system...

(a.k.a. CARD15) gene.