[Blau syndrome--a chronic granulomatous, genetic disease].

Blau syndrome is a rare hereditary granulomatous disease presenting in patients of young age with exanthema, granulomatous arthritis and uveitis. Genetic analysis has shown an autosomal dominant inheritance and a number of specific mutations on chromosome 16q in codon 334, of which the most predominant are R334W and R334Q. Blau syndrome exists in Caucasian, Asian and Afro-American families, and de novo mutations have been reported. The estimated minimum incidence in Denmark is 0.05 per 100,000 person-years. Blau syndrome has pathological, clinical and therapeutic features in common with sarcoidosis but rarely involves the lungs or other parenchymatous organs. Discrimination between Blau syndrome and early-onset sarcoidosis should rely on chromosome analysis.