Hypocomplementemic urticarial vasculitis syndrome (HUVS) is characterized by recurrent urticaria along with dermal vasculitis, arthritis, and glomerulonephritis. Systemic lupus erythematosus (SLE) develops in >50% of patients with HUVS, although the pathogenesis is unknown. The aim of this study was to identify the causative DNA mutations in 2 families with autosomal-recessive HUVS, in order to reveal the pathogenesis and facilitate the laboratory diagnosis.Methods
Autozygosity mapping was combined with whole-exome sequencing.Results
In a family with 3 affected children, we identified a homozygous frameshift mutation, c.289_290delAC, inDNASE1L3. We subsequently identified another homozygousDNASE1L3mutation leading to exon skipping, c.320+4delAGTA, in an unrelated family. The detected mutations led to loss of function, via either nonsense-mediated messenger RNA decay or abolished endonuclease activity, as demonstrated by a plasmid nicking assay.Conclusion
These results show that HUVS is caused by mutations inDNASE1L3, encoding an endonuclease that previously has been associated with SLE.