Case report: Novel compound heterozygous IL1RN mutations as the likely cause of a lethal form of deficiency of interleukin-1 receptor antagonist.

Undiagnosed monogenic diseases represent a challenging group of human conditions highly suspicious to have a genetic origin, but without conclusive evidences about it. We identified two brothers born prematurely from a non-consanguineous healthy couple, with a neonatal-onset, chronic disease characterized by severe skin and bone inflammatory manifestations and a fatal outcome in infancy. We conducted DNA and mRNA analyses in the patients' healthy relatives to identify the genetic cause of the patients' disease. DNA analyses were performed by both Sanger and next-generation sequencing, which identified two novel heterozygous IL1RN variants: the intronic c.318 + 2T>G variant in the father and a ≈2,600-bp intragenic deletion in the mother. IL1RN mRNA production was markedly decreased in both progenitors when compared with healthy subjects. The mRNA sequencing performed in each parent identified two novel, truncated IL1RN transcripts. Additional experiments revealed a perfect intrafamilial phenotype-genotype segregation following an autosomal recessive inheritance pattern. The evidences shown here supported for the presence of two novel loss-of-function (LoF) IL1RN pathogenic variants in the analyzed family. Biallelic LoF variants at the IL1RN gene cause the deficiency of interleukin-1 receptor antagonist (DIRA), a monogenic autoinflammatory disease with marked similarities with the patients described here. Despite the non-availability of the patients' samples representing the main limitation of this study, the collected evidences strongly suggest that the patients described here suffered from a lethal form of DIRA likely due to a compound heterozygous genotype at IL1RN, thus providing a reliable genetic diagnosis based on the integration of old medical information with currently obtained genetic data.

Vision-threatening bilateral panuveitis and TRAPS in a child: an uncommon association.

PURPOSE: To report a childhood case of tumor necrosis factor receptor-associated periodic syndrome (TRAPS) carrying the R92Q variant with a vision-threatening bilateral panuveitis. METHODS: Case report and review of the literature. RESULTS: A 7-year-old boy presented with an active bilateral panuveitis and a macular rash associated with fever. Fundus examination showed two choroidal lesions on the posterior pole of the right eye, and fluorescein angiography revealed early hypofluorescence and late hyperfluorescence of the lesions, which were hyper-autofluorescent. Extensive clinical laboratory analyses ruled out autoimmune diseases and systemic infection. The only remarkable finding was a positive IgG for herpes simplex 1. He underwent two successive diagnostic pars plana vitrectomies as well as cataract and glaucoma surgeries. Genetic analysis revealed a mutation in the TNFRSF1A gene, and the patient was diagnosed with TRAPS-associated bilateral panuveitis. He was treated with adalimumab and has been free of active inflammation since then. CONCLUSIONS: We present here the first case reported of panuveitis in a patient with TRAPS. This finding stresses the increasing importance of genetic analysis in search of autoinflammatory diseases to establish an adequate diagnosis and treatment in cases of uveitis of unknown etiology.