Behçet disease is most common in Mediterranean countries, the Middle East, Japan, and other parts of Asia. However, it has been found in populations worldwide.

The highest prevalence of Behçet disease has been reported in Turkey, where the disorder affects up to 420 in 100,000 people. The disorder is much less common in northern European countries and the United States, where it generally affects fewer than 1 in 100,000 people.

Source: Genetics Home Reference
http://ghr.nlm.nih.gov/condition/behcet-disease
Reviewed July 2010