Definition:

Behcet disease is a multisystemic inflammatory disease characterized by relapsing episodes of oral aphthous ulcers, genital ulcers, other skin lesions, and uveitis. It can also involve visceral organs such as the gastrointestinal tract, pulmonary, musculoskeletal, cardiovascular and neurological systems. This disease is more common in countries along the ancient Silk Road, including Asia, Middle East, and Mediterranean. Although the etiology is still unknown, this disease is believed to be triggered by environmental factors such as microbial agents in individuals with a particular genetic background. The positive association of HLA-B51 was identified more than four decades ago, and has been confirmed in multiple populations. Recent genome-wide association study identifies variants in the MHC class I, IL10, and IL23R-IL12RB2 regions associated with Behcet disease.