Blau syndrome

Blau syndrome is a rare condition characterized mainly by skin rash, arthritis and uveitis. It has variable expressivity and usually affects preschool age children younger than four years of age. Characteristic findings include synovial effusions (fluid in the joints due to inflammation) and cysts, anterior uveitis (swelling and irritation of the uvea) and focal posterior synechiae (adhesion of the iris to the cornea). Permanent bending of the fingers and toes (camptodactyly) and other findings have also been reported. It is caused by mutations in the NOD2 gene and is inherited in an autosomal dominant manner. Blau syndrome and early-onset sarcoidosis have the same symptoms and genetic cause, but early-onset sarcoidosis is caused by de novo (new) mutations and occurs sporadically (in individuals with no history of the disorder in the family).