Open AccessMutations of the hemophagocytic lymphohistiocytosis–associated gene UNC13D in a patient with systemic juvenile idiopathic arthritis
Author(s) -
Hazen Melissa M.,
Woodward Amy L.,
Hofmann Inga,
Degar Barbara A.,
Grom Alexei,
Filipovich Alexandra H.,
Binstadt Bryce A.
Publication year - 2008
Publication title -
arthritis & rheumatism
Language(s) - English
Resource type - Journals
eISSN - 1529-0131
pISSN - 0004-3591
DOI - 10.1002/art.23199
Subject(s) - macrophage activation syndrome , hemophagocytic lymphohistiocytosis , hemophagocytosis , perforin , immunology , hepatosplenomegaly , compound heterozygosity , medicine , systemic inflammation , cytotoxic t cell , arthritis , phenotype , biology , inflammation , bone marrow , gene , genetics , cd8 , disease , pancytopenia , immune system , in vitro
The clinical syndromes of hemophagocytic lymphohistiocytosis (HLH) and macrophage activation syndrome (MAS) are both characterized by dysregulated inflammation with prolonged fever, hepatosplenomegaly, coagulopathy, hematologic cytopenias, and evidence of hemophagocytosis in the bone marrow or liver. While HLH is either inherited or acquired, children with severe rheumatic diseases, most notably systemic juvenile idiopathic arthritis, are at risk for MAS. The phenotypic similarity between HLH and MAS raises the possibility that they share common pathogenetic mechanisms. Familial forms of HLH have been attributed to mutations in the genes encoding perforin ( PRF1 ) and Munc13‐4 ( UNC13D ), among others, and are characterized by defective cytotoxic lymphocyte function. While some patients with systemic JIA have decreased levels of perforin protein expression and natural killer (NK) cell function, mutations of HLH‐associated genes in patients with systemic JIA have not been reported. We report the case of an 8‐year‐old girl with systemic JIA without MAS who was found to have compound heterozygous mutations of UNC13D and reduced NK cell cytotoxic function. This case broadens the range of clinical phenotypes attributable to UNC13D mutations and offers new insights into the etiology and pathogenesis of systemic JIA.