Behçet disease is an inflammatory condition that affects many parts of the body. The health problems associated with Behçet disease result from widespread inflammation of blood vessels (vasculitis). This inflammation most commonly affects small blood vessels in the mouth, genitals, skin, and eyes.\n\nPainful mouth sores called aphthous ulcers are usually the first sign of Behçet disease. These sores can occur on the lips, tongue, inside the cheeks, the roof of the mouth, the throat, and the tonsils. The ulcers look like common canker sores, and they typically heal within one to two weeks. About 75 percent of all people with Behçet disease develop similar ulcers on the genitals. These ulcers occur most frequently on the scrotum in men and on the labia in women.\n\nBehçet disease can also cause painful bumps and sores on the skin. Most affected individuals develop pus-filled bumps that resemble acne. These bumps can occur anywhere on the body. Some affected people also have red, tender nodules called erythema nodosum. These nodules usually develop on the legs but can also occur on the arms, face, and neck.\n\nAn inflammation of the eye called uveitis is found in more than half of people with Behçet disease. Eye problems are more common in younger people with the disease and affect men more often than women. Uveitis can result in blurry vision and an extreme sensitivity to light (photophobia). Rarely, inflammation can also cause eye pain and redness. If untreated, the eye problems associated with Behçet disease can lead to blindness.\n\nJoint involvement is also common in Behçet disease. Often this affects one joint at a time, with each affected joint becoming swollen and painful and then getting better.\n\nLess commonly, Behçet disease can affect the brain and spinal cord (central nervous system), gastrointestinal tract, large blood vessels, heart, lungs, and kidneys. Central nervous system abnormalities can lead to headaches, confusion, personality changes, memory loss, impaired speech, and problems with balance and movement. Involvement of the gastrointestinal tract can lead to a hole in the wall of the intestine (intestinal perforation), which can cause serious infection and may be life-threatening.\n\nThe signs and symptoms of Behçet disease usually begin in a person's twenties or thirties, although they can appear at any age. Some affected people have relatively mild symptoms that are limited to sores in the mouth and on the genitals. Others have more severe symptoms affecting various parts of the body, including the eyes and the vital organs. The features of Behçet disease typically come and go over a period of months or years. In most affected individuals, the health problems associated with this disorder improve with age.

Severe combined immunodeficiency (SCID) due to DCLRE1C deficiency is a type of SCID (see this term) characterized by severe and recurrent infections, diarrhea, failure to thrive, and cell sensitivity to ionizing radiation.

Familial Behcet-like autoinflammatory syndrome-1 (AIFBL1) is an autosomal dominant monogenic autoinflammatory disease characterized predominantly by painful and recurrent mucosal ulceration affecting the oral mucosa, gastrointestinal tract, and genital areas. The onset of symptoms is usually in the first decade, although later onset has been reported. Additional more variable features include skin rash, uveitis, and polyarthritis, consistent with a systemic hyperinflammatory state. Many patients have evidence of autoimmune disease. Rare patients may also have concurrent features of immunodeficiency, including recurrent infections with low numbers of certain white blood cells or impaired function of immune cells. The disorder results from a failure of mutant TNFAIP3 to suppress the activation of inflammatory cytokines in the NFKB (see 164011) signaling pathway; treatment with tumor necrosis factor (TNFA; 191160) inhibitors may be beneficial. Although some of the clinical features of AIFBL1 resemble those of Behcet disease (109650), the more common form of Behcet disease is believed to be polygenic, typically shows later onset in early adulthood, and has symptoms usually restricted to the mucosa (summary by Zhou et al., 2016; Aeschlimann et al., 2018, and Kadowaki et al., 2018). Genetic Heterogeneity of AIFBL See also AIFBL2 (301074), caused by mutation in the ELF4 gene (300775) on chromosome Xq26, and AIFBL3 (618287), caused by mutation in the RELA gene (164014) on chromosome 11q13.