This study was undertaken to describe the expanded clinical phenotype, treatment outcomes, and NOD2 gene mutation analysis in a Spanish cohort with pediatric granulomatous arthritis, a chronic disease resembling Blau syndrome/early-onset sarcoidosis.
Blau's syndrome (familial juvenile systemic granulomatosis) presents with non-caseating granulomatous inflammation affecting the joint, skin, and uveal tract (the triad of arthritis, dermatitis and uveitis) and is associated with mutations of the NACHT domain of the gene CARD15 (or NOD2).
Mutations and polymorphisms in the NOD2/CARD15 gene reduce antibacterial responses and are associated with granulomatous inflammatory conditions such as Blau syndrome and early-onset sarcoidosis.
Early-onset sarcoidosis (EOS), which occurs in children younger than 5 years of age, is associated with granulomatous lesions and a sporadic genetic mutation of the nucleotide-binding oligomerization domain 2 that causes constitutive NF-kappaB activation.
A family history of uveitis supported a diagnosis of Blau syndrome, and analysis of the NOD2 gene revealed a heterozygous gain-of-function missense mutation (Arg334Trp) that has previously been detected in Blau syndrome kindreds.
In addition, recent evidence has demonstrated that mutations in Nod1 and Nod2 are associated with a number of human inflammatory disorders, including Crohn's disease, Blau syndrome, early-onset sarcoidosis, and atopic diseases.
The association of NOD2 mutations with a number of inflammatory pathologies, including Crohn disease (CD), Graft-versus-host disease (GVHD), and Blau syndrome, highlights its pivotal role in host-pathogen interactions and inflammatory response.
Blau syndrome (BS) is a rare dominantly inherited autoinflammatory disorder associated with mutations in the nucleotide-binding oligomerization domain containing 2 (NOD2) gene.
A 4-year-old boy was diagnosed as having Blau syndrome on the basis of typical clinical features, histologic evidence of noncaseating granulomas, and a NOD2 mutation.