About Blau Syndrome

Blau syndrome is a rare inflammatory disorder that primarily affects the skin, joints, and eyes. Signs and symptoms begin in childhood, usually before age 4. A form of skin inflammation called granulomatous dermatitis is typically the earliest sign of Blau syndrome. This skin condition causes a persistent rash that can be scaly or involve hard lumps that can be felt under the skin. The rash is usually found on the torso, arms, and legs. Arthritis is another common feature of Blau syndrome. In affected individuals, arthritis is characterized by inflammation of the lining of joints (the synovium). This inflammation, known as synovitis, is associated with swelling and joint pain. Synovitis usually begins in the joints of the hands, feet, wrists, and ankles. As the condition worsens, it can restrict movement by decreasing the range of motion in many joints.

Most people with Blau syndrome also develop uveitis, which can cause eye irritation and pain, increased sensitivity to bright light, and blurred vision. Other structures in the eye can also become inflamed. Inflammation of any of these structures can lead to severe vision impairment or blindness. Less commonly, Blau syndrome can affect other parts of the body, including the liver, kidneys, brain, blood vessels, lungs, and heart. Inflammation involving these organs and tissues can cause life-threatening complications.

Blau syndrome results from mutations in the NOD2 (aka CARD15) gene. The protein produced from this gene helps defend the body from foreign invaders, such as viruses and bacteria, by playing several essential roles in the immune response, including inflammatory reactions. The NOD2 gene mutations in Blau syndrome result in a loss of immune function, whereby certain bacteria cannot be recognized and eliminated. The NOD2 gene is also one of the susceptibility genes for Crohn’s disease.

Blau syndrome is an inherited condition where one copy of the altered gene in each cell is sufficient to cause the disorder. Most affected individuals have one parent with the condition. In some cases, people with the characteristic features of Blau syndrome do not have a family history of the condition. In these cases the affected person has a de novo defect of the NOD2 gene identical to that of those who have the inherited mutation.

The Possible Role of MAP in Blau Syndrome

Mycobacterium avium spp paratuberculosis (MAP) has been found in a number of different human diseases. The role that MAP plays in any of these conditions is still the subject of debate, and further research is necessary. Human Para will add research studies as they are released.

Detection of Mycobacterium avium ss. Paratuberculosis in Blau syndrome tissues.  (June 2010)
Six tissue samples from five Blau syndrome patients were tested for two different MAP DNA markers (IS900 and hspX). Of thje six samples tested, all were positive for the IS900 MAP marker and three were positive for the more specific hspX marker. The researchers conclude that the NOD2/CARD15 gene defect associated with Blau syndrome allows for a persistent presence of MAP. However, larger scale studies which include MAP testing of these patients are necessary.