Objective

Chronic atypical neutrophilic dermatosis with lipodystrophy and elevated temperature (CANDLE) syndrome is an autoinflammatory syndrome recently described in children. We investigated the clinical phenotype, genetic cause and the immune dysregulation in nine CANDLE patients.

Methods

Genomic DNA from all patients was screened for PSMB8 (Proteasome subunit beta type-8) mutations. Serum cytokine levels were measured from four patients. Skin biopsies were evaluated immunohistochemically and blood microarray profile (n= 4) and stat-1 phosphorylation (n= 3) were assessed.

Results

One patient was homozygous for a novel nonsense mutation in PSMB8 (c. 405C> A) suggesting a protein truncation, four patients were homozygous and two were heterozygous for a previously reported missense mutation (c. 224C> T), and one patient showed no mutation. None of these sequence changes was observed in chromosomes from 750 healthy controls. Of the four patients with the same mutation, only two share the same haplotype indicating a mutational hot spot. PSMB8 mutation-positive and-negative patients expressed high IP-10 (Interferon gamma-induced protein 10) levels. Levels of MCP-1, IL-6, and IL-1Ra were moderately elevated. Microarray profiles and monocyte stat-1 activation suggested a unique interferon (IFN) signaling signature, unlike in other autoinflammatory disorders.

Conclusion

CANDLE is caused by mutations in PSMB8, a gene recently reported to cause JMP syndrome (joint contractures, muscle atrophy and panniculitis induced lipodystrophy) in adults. We extend the clinical and pathogenic description of this novel autoinflammatory syndrome, thereby expanding the clinical and genetic disease spectrum of PSMB8-associated disorders. IFN may be a key mediator of the inflammatory response and may present a therapeutic target.