TRAF1/C5 was among the first loci shown to confer risk for inflammatory arthritis in the absence of an associated coding variant, but its genetic mechanism remains undefined. Using Immunochip data from 3,939 patients with juvenile idiopathic arthritis (JIA) and 14,412 control individuals, we identified 132 plausible common non-coding variants, reduced serially by single-nucleotide polymorphism sequencing (SNP-seq), electrophoretic mobility shift, and luciferase studies to the single variant rs7034653 in the third intron of TRAF1. Genetically manipulated experimental cells and primary monocytes from genotyped donors establish that the risk G allele reduces binding of Fos-related antigen 2 (FRA2), encoded by FOSL2, resulting in reduced TRAF1 expression and enhanced tumor necrosis factor (TNF) production. Conditioning on this JIA variant eliminated attributable risk for rheumatoid arthritis, implicating a mechanism shared across the arthritis spectrum. These findings reveal that rs7034653, FRA2, and TRAF1 mediate a pathway through which a non-coding functional variant drives risk of inflammatory arthritis in children and adults.

Background The prevalence of Celiac Disease (CD) in Juvenile Idiopathic Arthritis (JIA) has been reported to be 0.1–7% in various small studies. As a result of the limited number of research and their inconclusive results there are no clear recommendations for routine CD screening in asymptomatic patients with JIA. Our aim is to estimate the prevalence of IgA deficiency and tissue transglutaminase (tTG) IgA in a cohort of JIA followed in two large academic medical centers. Methods Serum was collected and stored from all subjects and analyzed in a reference laboratory for total IgA (Quantitative Nephelometry) and tTG IgA antibody levels (Semi-Quantitative Enzyme-Linked Immunosorbent Assay). Fisher’s exact tests were performed for statistical significance. Risk estimates (odds ratios) with 95% confidence intervals were calculated. Results 808 JIA cases and 140 controls were analyzed. Majority were non-Hispanic whites (72% vs. 68% p = 0.309). A total of 1.2% of cases were IgA deficient compared to none of the controls (p = 0.373). After excluding IgA deficient subjects, 2% of cases had tTG IgA ≥ 4u/mL compared to 3.6% of controls (p = 0.216) (OR = 0.5; 95% C.I = 0.1–1.4); and 0.8% of cases had tTG IgA > 10u/mL compared to 1.4% of controls (p = 0.627) (OR = 0.5; 95%C.I = 0.1–2.9). Conclusions Using the largest JIA cohort to date to investigate prevalence of celiac antibodies, the prevalence of positive tTG IgA was 0.8% and of IgA deficiency was 1.2%. The results did not demonstrate a higher prevalence of abnormal tTG IgA in JIA. The study did not support the routine screening of asymptomatic JIA patients for CD.

Objective: To investigate the characteristics and risk factors of a novel parenchymal lung disease (LD), increasingly detected in systemic juvenile idiopathic arthritis (sJIA). Methods: In a multicentre retrospective study, 61 cases were investigated using physician-reported clinical information and centralised analyses of radiological, pathological and genetic data. Results: LD was associated with distinctive features, including acute erythematous clubbing and a high frequency of anaphylactic reactions to the interleukin (IL)-6 inhibitor, tocilizumab. Serum ferritin elevation and/or significant lymphopaenia preceded LD detection. The most prevalent chest CT pattern was septal thickening, involving the periphery of multiple lobes ± ground-glass opacities. The predominant pathology (23 of 36) was pulmonary alveolar proteinosis and/or endogenous lipoid pneumonia (PAP/ELP), with atypical features including regional involvement and concomitant vascular changes. Apparent severe delayed drug hypersensitivity occurred in some cases. The 5-year survival was 42%. Whole exome sequencing (20 of 61) did not identify a novel monogenic defect or likely causal PAP-related or macrophage activation syndrome (MAS)-related mutations. Trisomy 21 and young sJIA onset increased LD risk. Exposure to IL-1 and IL-6 inhibitors (46 of 61) was associated with multiple LD features. By several indicators, severity of sJIA was comparable in drug-exposed subjects and published sJIA cohorts. MAS at sJIA onset was increased in the drug-exposed, but was not associated with LD features. Conclusions: A rare, life-threatening lung disease in sJIA is defined by a constellation of unusual clinical characteristics. The pathology, a PAP/ELP variant, suggests macrophage dysfunction. Inhibitor exposure may promote LD, independent of sJIA severity, in a small subset of treated patients. Treatment/prevention strategies are needed.

Juvenile idiopathic arthritis (JIA) is the most common chronic inflammatory arthropathy of childhood. Juvenile idiopathic arthritis is believed to be a complex genetic trait influenced by both genetic and environmental factors. Twin and family studies suggest a substantial role for genetic factors in the predisposition to JIA. Describing the genetics is complicated by the heterogeneity of JIA; the International League of Associations for Rheumatology (ILAR) has defined seven categories of JIA based on distinct clinical and laboratory features. Utilizing a variety of techniques including candidate gene studies, the use of genotyping arrays such as Immunochip, and genome wide association studies (GWAS), both human leukocyte antigen (HLA) and non-HLA susceptibility loci associated with JIA have been described. Several of these polymorphisms (e.g. HLA class II, PTPN22, STAT4) are shared with other common autoimmune conditions; other novel polymorphisms that have been identified may be unique to JIA.Associations with oligoarticular and RF-negative polyarticular JIA are the best characterized. A strong association between HLA DRB1:. 11:03/04 and DRB1:08:01, and a protective effect of DRB1:15:01 have been described. HLA DPB1:02:01 has also been associated with oligoarticular and RF-negative polyarticular JIA. Besides PTPN22, STAT4 and PTPN2 variants, IL2, IL2RA, IL2RB, as well as IL6 and IL6R loci also harbor variants associated with oligoarticular and RF-negative polyarticular JIA. RF-positive polyarticular JIA is associated with many of the shared epitope encoding HLA DRB1 alleles, as well as PTPN22, STAT4 and TNFAIP3 variants. ERA is associated with HLA B27. Most other associations between JIA categories and HLA or non-HLA variants need confirmation. The formation of International Consortia to ascertain and analyze large cohorts of JIA categories, validation of reported findings in independent cohorts, and functional studies will enhance our understanding of the genetic underpinnings of JIA.

Purpose: To identify risk factors for a severe uveitis course among children with non-infectious uveitis. Design: Retrospective cohort study Method: This was a retrospective analysis of a prospectively collected database. Records of 94 children with uveitis were reviewed at enrollment and every 3-6 months (2011-2015). Severe uveitis was defined as a history of ocular complications or a visual acuity (VA) of ≤20/200. Children were compared by disease, VA, complications and race. Regression models were used to model risk factors for severe disease. When examining race, we focused on non-Hispanic African American and non-Hispanic White children only. Results: Of 85 children with uveitis and complete ocular examinations, 27 (32%) had a history of a VA of ≤20/200. A subanalysis of non-Hispanic African American and White children showed an increased prevalence of VA ≤20/200 in non-Hispanic African Americans (18/25 (72%) vs. 4/43 (9%)). Non-Hispanic African Americans were more likely to be diagnosed at an older age (p=0.030), have intermediate uveitis (p=0.026), bilateral disease (p=0.032), a history of VA ≤20/50 (p=0.002), VA ≤20/200 (p<0.001), and a higher rate of complications (p<0.001). On multivariable analysis, non-Hispanic African American race was a significant predictor of blindness (OR=31.6, 95% CI (5.9– 168.5), p<0.001), after controlling for uveitis duration. Non-Hispanic African Americans also developed 2.2 times more unique complications per year of disease than non-Hispanic Whites when controlling for uveitis type and duration. Conclusions: There appear to be racial differences in the outcomes of children with uveitis. Non-Hispanic African American children with non-juvenile idiopathic arthritis associated uveitis may have worse visual outcomes with increased vision loss and ocular complications. These findings highlight the need for future studies in minority populations.

Objective: The Effects of Youngsters’ Eyesight on Quality of Life (EYE-Q) is a novel measure of vision-related quality of life (QOL) and function in children. We aim to determine the validity of EYE-Q in childhood uveitis. Methods: We abstracted medical record data on arthritis and uveitis in a convenience sample of children with juvenile idiopathic arthritis (JIA) and/or uveitis. In addition to the EYE-Q, parents and patients completed questionnaires on overall QOL (Pediatric QOL Inventory - PedsQL), and physical functioning (Childhood Health Assessment Questionnaire - CHAQ). Results: Among 57 children (8 JIA, 24 JIA and uveitis, 25 uveitis alone), 102 ocular examinations were performed within 1 month of completing questionnaires. Uveitis patients had bilateral disease (69%), anterior involvement (78%), synechiae (51%) and cataracts (49%). Children with vision loss in their better eye (visual acuity (VA) 20/50 or worse) had worse EYE-Q (p = 0.006), and PedsQL (p = 0.028), but not CHAQ scores. The EYE-Q moderately correlated with logMAR VA (rs = −0.43), PedsQL (rs = 0.43) and CHAQ (rs = −0.45), but was not correlated with anterior chamber cells or intraocular pressure. The PedsQL and CHAQ did not correlate with VA or cells. There were strong correlations between the parent and child EYE-Q (rs = 0.62). Cronbach's α for the child report was 0.91. The EYE-Q had strong test-retest reliability (rs=0.75). Conclusion: The EYE-Q may be an important tool in the assessment of visual outcomes in childhood uveitis and an improvement over general measures in detecting changes in vision-related function.

Crohn's disease is a complex genetic trait characterized by chronic relapsing intestinal inflammation. Genome wide association studies (GWAS) have identified more than 170 loci associated with the disease, accounting for ~14% of the disease variance. We hypothesized that rare genetic variation in GWAS positional candidates also contribute to disease pathogenesis. We performed targeted, massively-parallel sequencing of 101 genes in 205 children with Crohn's disease, including 179 parent-child trios and 200 controls, both of European ancestry.We used the gene burden test implemented in VAAST and estimated effect sizes using logistic regression and meta-analyses. We identified three genes with nominally significant p-values: NOD2, RTKN2, and MGAT3. Only NOD2 was significant after correcting for multiple comparisons. We identified eight novel rare variants in NOD2 that are likely disease-associated. Incorporation of rare variation and compound heterozygosity nominally increased the proportion of variance explained from 0.074 to 0.089. We estimated the population attributable risk and total heritability of variation in NOD2 to be 32.9% and 3.4%, respectively, with 3.7% and 0.25% accounted for by rare putatively functional variants. Sequencing probands (as opposed to genotyping) to identify rare variants and incorporating phase by sequencing parents can recover a portion of the missing heritability of Crohn's disease.

Objectives: Inflammatory bowel disease (IBD) is heritable, but a total of 163 variants commonly implicated in IBD pathogenesis account for only 25% of the heritability. Rare, highly penetrant genetic variants may also explain mendelian forms of IBD and some of the missing heritability. To test the hypothesis that rare loss-of-function mutations can be causative, we performed whole exome sequencing (WES) on 5 members of a 2-generation family of European ancestry presenting with an early-onset and atypical form of IBD. Methods: WES was performed for all of the 5 family members; the mother and 3 male offspring were affected, whereas the father was unaffected. Mapping, annotation, and filtering criteria were used to reduce candidate variants. For functional testing we performed forkhead box P3 (FOXP3) staining and a T-cell suppression assay. Results: We identified a novel missense variant in exon 6 of the X-linked FOXP3 gene. The c.694A>C substitution in FOXP3 results in a cysteine-to-glycine change at the protein position 232 that is completely conserved among all vertebrates. This variant (heterozygous in the mother and hemizygous in all 3 affected sons) did not impair FOXP3 protein expression, but significantly reduced the ability of the host's T regulatory cells to suppress an inappropriate autoimmune response. The variant results in a milder immune dysregulation, polyendocrinopathy, enteropathy, and X-linked phenotype with early-onset IBD. Conclusions: Our study illustrates the successful application of WES for making a definitive molecular diagnosis in a case of multiply affected families, with atypical IBD-like phenotype. Our results also have important implications for disease biology and disease-directed therapeutic development.

Objective: To characterize the epidemiology and clinical course of children with juvenile idiopathic arthritis-associated uveitis (JIA-U) in the Childhood Arthritis and Rheumatology Research Alliance (CARRA) Registry and explore differences between African American (AA) and non-Hispanic white (NHW) children. Methods: There were 4983 children with JIA enrolled in the CARRA Registry. Of those, 3967 NHW and AA children were included in this study. Demographic and disease-related data were collected from diagnosis to enrollment. Children with JIA were compared to those with JIA-U. Children with JIA-U were also compared by race. Results: There were 459/3967 children (11.6%) with JIA-U in our cohort with a mean age (SD) of 11.4 years (± 4.5) at enrollment. Compared to children with JIA, they were younger at arthritis onset, more likely to be female, had < 5 joints involved, had oligoarticular JIA, and were antinuclear antibody (ANA)-positive, rheumatoid factor (RF)-negative, and anticitrullinated protein antibody-negative. Predictors of uveitis development included female sex, early age of arthritis onset, and oligoarticular JIA. Polyarticular RF-positive JIA subtype was protective. Nearly 3% of children with JIA-U were AA. However, of the 220 AA children with JIA, 6% had uveitis; in contrast, 12% of the 3721 NHW children with JIA had uveitis. Conclusion: In the CARRA registry, the prevalence of JIA-U in AA and NHW children is 11.6%. We confirmed known uveitis risk markers (ANA positivity, younger age at arthritis onset, and oligoarticular JIA). We describe a decreased likelihood of uveitis in AA children and recommend further exploration of race as a risk factor in a larger population of AA children.