Behcet's Disease Risk Factors and Causes
The cause of Behcet's disease is unknown. A combination of genetic (inherited) immune system abnormalities and environmental risk factors may play a role in development of the disease. There is some evidence that a virus (e.g., herpesvirus type 1) or bacteria (Streptococcus, which causes strep throat) may contribute to Behcet's disease.
In areas of the world where the disorder is more common (e.g., the Mediterranean, East Asia), genetic studies have shown that Behcet's disease may be linked to the presence of human leukocyte antigen B5 (HLA-B51). However, a true cause and effect relationship has not been proven. In fact, patients with the disease who live outside this area usually do not have this gene.