The arthritis is a rare autoinflammatory condition where the blood vessels and tissues may become swollen.
In the UK there are just 2,000 people currently living with it.
According to Arthritis Research UK, it affects men and women of all ages – but is most likely to develop in your 20s and 30s and is more common in those from Mediterranean countries.
It’s named after Professor Hulusi Behçet, a Turkish skin specialist who was the first person to suggest mouth ulcers, genital ulcers and eye inflammation could be linked to a single disease.
While the exact cause isn’t known, it’s thought to be associated with the immune system.
Indeed, an autoinflammatory condition is one where the body’s immune system mistakenly attacks its own healthy cells.
With this disease, the inflammation can occur anywhere in the body.
There are a large number of symptoms, but it’s unlikely a sufferer would have them all.
It’s common for them to have mouth ulcers, while half of patients experience inflammation of the eyes.
Other signs include genital ulcers, skin lesions, inflammation of the joints and sensitive skin.
It can also cause gastrointestinal problems, triggering nausea, vomiting, indigestion, loss of appetite and diarrhoea.
Blood clots and skin lesions can also be signs.
The disease can’t be passed onto other people.
It’s also not associated with any other condition, diet or lifestyle, according to Arthritis Research UK.
While there’s currently no cure, early diagnosis and treatment can help.
Because it can affect several parts of the body, patients might need to see a number of specialists.