title: Blau syndrome revisited.
abstract: OBJECTIVE
  Blau syndrome is a monogenic disease resulting from mutations in nucleotide oligomerization domain 2 (NOD2) and is phenotypically characterized by granulomatous polyarthritis and uveitis. Not only there has been significant progress in disease characterization but also the biological pathways associated with NOD2 and related proteins of the innate immunity are better understood.
  
  
  RESULTS
  The phenotype of Blau syndrome has proven to be more complex than initially thought. A discussion on those manifestations will be provided in the clinical sections of this review. As more patients and pedigrees are found new mutations in the NOD2 gene have emerged and we discuss them in some detail. Due to its importance in Crohn's disease NOD2 has become the focus of intense research. A brief review of more recent advances in relevant pathways is presented and published reviews referenced for the interested reader. The granulomatous character of Blau syndrome provides an opportunity to look at possible pathogenic effects of NOD2 'gain of function'. New immunohistochemical data are briefly reviewed as well.
  
  
  CONCLUSIONS
  Elucidation of downstream effects of NOD2 mutations could provide valuable clues to mechanisms of arthritis and uveitis in general as well as granulomatous diseases in particular.
authors.affiliation: Thomas Jefferson University and duPont Children's Hospital, Wilmington, Delaware, USA.
authors.forename: Carlos D
authors.initials: CD
authors.lastname: Rose
authors.forename: Tammy M
authors.initials: TM
authors.lastname: Martin
authors.forename: Carine H
authors.initials: CH
authors.lastname: Wouters
mesh_terms: D000818:Animals; D001168:Arthritis; D003389:Cranial Nerve Diseases / Q000235:genetics* / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D008024:Ligands; D009154:Mutation; D053473:Nod2 Signaling Adaptor Protein / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010641:Phenotype; D012507:Sarcoidosis; D015398:Signal Transduction; D013577:Syndrome; D013585:Synovitis / Q000235:genetics* / Q000276:immunology* / Q000378:metabolism; D009626:Terminology as Topic; D014605:Uveitis / Q000235:genetics* / Q000276:immunology* / Q000378:metabolism; D056660:Hereditary Autoinflammatory Diseases
chemical_list: D008024:Ligands; C429018:NOD2 protein, human; D053473:Nod2 Signaling Adaptor Protein