Blau syndrome is an autosomal dominant genetic inflammatory disorder which affects the skin, eyes, and joints.
It is caused by a mutation in the NOD2 (CARD15) gene.
Symptoms usually begin before the age of four, and the disease manifests as early onset cutaneous sarcoidosis, granulomatous arthritis, and uveitis.
The innate immune system recognizes pathogen-associated molecular patterns, including bacterial polysaccharides such as muramyl dipeptide, via its pattern recognition receptors to induce signaling pathways that activate cytokine responses and protect the organism.
In BS the genetic defect leads to over activation and poor control of the inflammatory response leading to widespread granulomatous inflammation and tissue damage.
Treatment has included the usual anti-inflammatory drugs such as adrenal glucocorticoids, anti-metabolites and also biological agents such as anti-TNF and infliximab all with varying degrees of success.