OBJECTIVE To report cases of Blau syndrome with a CARD15/Nod2 mutation. METHODS Observational and interventional case report. METHODS A 10-year-old Japanese boy (proband) was seen with secondary angle-closure glaucoma (iris bombe), uveitis, skin rashes, and camptodactyly. His sister had posterior synechia and camptodactyly. She had iritis in both eyes during the follow-up period. Both eyes of the father were phthisical because of granulomatous uveitis and secondary glaucoma. The father also had camptodactyly. METHODS Surgery was performed to release the iris bombe. Ocular inflammation was treated by topical and systemic steroids. Biopsy specimens from the skin rash and from the iris (from iridectomy) were obtained from the proband. Genetic analyses were performed on the proband, his sister, and their mother for a CARD15/Nod2 mutation. METHODS Clinical features, pathologic findings of the skin and iris specimens, and genetic analysis of the CARD15/Nod2 gene. RESULTS Phacoemulsification, intraocular lens implantation, and peripheral iridectomy released the iris bombe. The biopsy specimen from the skin rash showed noncaseating, granulomatous infiltration with epithelioid cells and lymphocytes. The iridectomy specimen showed nonspecific inflammation. Systemic and topical steroid therapy partly reduced the ocular inflammation. Genetic analyses showed that the proband and his sister had an R334W mutation in the CARD15/Nod2 gene, but their mother was of the wild type. CONCLUSIONS Blau syndrome should be considered in the differential diagnosis of childhood uveitis. Genetic analysis of the CARD15/Nod2 gene is helpful in the diagnosis.