What are the genetic changes related to Behet disease ?
The cause of Behet disease is unknown. The condition probably results from a combination of genetic and environmental factors, most of which have not been identified. However, a particular variation in the HLA-B gene has been strongly associated with the risk of developing Behet disease.  The HLA-B gene provides instructions for making a protein that plays an important role in the immune system. The HLA-B gene is part of a family of genes called the human leukocyte antigen (HLA) complex. The HLA complex helps the immune system distinguish the body's own proteins from proteins made by foreign invaders (such as viruses and bacteria). The HLA-B gene has many different normal variations, allowing each person's immune system to react to a wide range of foreign proteins. A variation of the HLA-B gene called HLA-B51 increases the risk of developing Behet disease. Although many people with Behet disease have the HLA-B51 variation, most people with this version of the HLA-B gene never develop the disorder. It is unknown how HLA-B51 increases the risk of developing Behet disease.  Researchers have considered many other genetic and environmental factors as possible contributors to Behet disease. Studies have examined several genes related to immune system function, although no gene except HLA-B has been definitively associated with an increased risk of Behet disease. It appears likely that environmental factors, such as certain bacterial or viral infections, play a role in triggering the disease in people who are at risk. However, the influence of genetic and environmental factors on the development of this complex disorder remains unclear.