This syndrome due to multisystem chronic inflammatory disease of blood vessels has variable presentation of recurrent mouth ulcers, genital ulcers, inflammation of the eye (Uveitis), and gastrointestinal symptoms. HLA-B*51:02 shows the strongest association with the disease, but it is not diagnostic. The disease distribution is worldwide but clusters in the area that extends from Eastern Asia to the Mediterranean region (Silk Route disease).
Reference
Takeno, Mitsuhiro. The association of Behcet's syndrome with HLA-B51 as understood in 2021, Current Opinion in Rheumatology: January 2022 - Volume 34 - Issue 1 - p 4-9