Behcet’s disease or Adamantiades–Behçet's disease (ABD) is a multisystem vasculopathy/vasculitis with the classic clinical signs of recurrent oral ulcers, genital ulcers, and uveitis. The classic signs are often accompanied by skin, arthritic, intestinal, and neurological involvement. The disease is found throughout the world, although mainly among individuals of Mediterranean and East-Asian descent along the ‘Silk Road’. Epidemiologic studies demonstrate a prevalence of ABD in the range of 0.12–420 per 100.000 inhabitants, with the highest numbers in Turkey and the lowest in the United States of America. The etiology of the disease remains unknown.
Genetic factors, infectious agents and environmental pollution, immunological mechanisms, and endothelial and clotting factors have been implicated and studied intensively.
Several lines of evidence suggest that host genetic factors play a pivotal role in determining susceptibility to BD. In particular, it has long been known that BD is associated with the major histocompatibility complex HLA–B5 allele and, more specifically, with HLA B*51.
HLA B*51 is, therefore, the most strongly associated risk factor for Behçet’s disease, which has been confirmed in multiple populations.