|Blau Syndrome (NOD2), also known as Pediatric Granulomatous Arthritis (PGA), or Juvenile Sarcoidosis|
Blau syndrome is a rare autoinflammatory disease that is caused my a mutation in the NOD2 (also known as CARD 15) gene. This condition is autosomal dominant, so it can be inherited from one parent, or it can occur as a spontaneous mutation.
One of the first signs of Blau is the presence of a rash in infancy or early childhood, often around 4 months of age. Arthritis is the most common finding in Blau patients, and starts within the first 10 years of life. The arthritis often causes cystic swelling of the wrists, ankles, elbow and fingers, with tenderness and erythema. A distinguishing feature in Blau patients is the presence of noncaseating granulomas present in skin, synovial (joint) or conjunctival (eye) biopsies. Patients can also have synovial cysts, and uveitis which can cause significant and permanent vision damage. Some patients also have inflammatory bowel disease symptoms. Crohns Disease, and inflammatory bowel disease, has been also found to have mutations in the NOD2/CARD 15 gene.
Blau can present as "typical" with the condition mostly affecting the skin, joints and eyes, or "atypical" where other organs in the body, including the kidney, liver and peripheral nerves are affected. Occasionally the lungs are affected as well.
Eye involvement, such as uveitis and/or iritis is the most damaging affect of Blau, and symptoms can present in early childhood to early adulthood. Uveitis can lead to cateracts, and increased pressure in the eye that can cause permanent vision damage.
References for this section include the following articles: http://www.jrheum.com/subscribers/07/12/2504.html
Please refer to this article for more information about Blau, along with images showing rashes, and skin biopsies of the noncaseating granulomas: http://dermatology.cdlib.org/1512/articles/blau/glass.html
This patient information sheet is available in many languages at: http://www.printo.it/pediatric-rheumatology/information/UK/13_2.htm