Blau arteritis resembling Takayasu disease with a novel NOD2 mutation.

Objective: To put forward a new concept--Blau arteritis, a form of large-vessel vasculitis phenotypically related to Takayasu disease but genetically and clinically part of an expanded phenotype of Blau syndrome.
Methods: We provide a clinical description of a new case and summarize previously published cases of arteritis associated with Blau syndrome. Genetic testing was performed by direct sequencing of exon 4 of the NOD2 gene.
Results: The case described and those reviewed from the literature demonstrate the emerging phenotype of Takayasu-like arteritis in patients with Blau syndrome. Although most patients described to date depict an otherwise classic Blau syndrome phenotype, the current case was atypical in that the predominant features were arteritic. A novel substitution, G464W, in a highly conserved position near the nucleotide oligomerization domain of the NOD2 protein is also described.
Conclusion: Blau arteritis can be observed in the context of both typical and atypical (incomplete) Blau syndrome. The associated mutation in the NOD2 gene raises the question of the potential importance of this gene among patients with "primary" forms of Takayasu arteritis.