Interstitial pneumonitis in Blau syndrome with documented mutation in CARD15

This is the first report of a CARD15 mutation–positive patient with Blau syndrome who exhibited interstitial lung disease, a feature historically considered absent from Blau syndrome, while typical of the adult form of sarcoidosis. This case illustrates the continued evolution of the phenotype of a disease initially conceived as a familial inflammatory granulomatous disease limited to the triad of synovitis, dermatitis, and uveitis.