OBJECTIVE:The objective of this study was to estimate the prevalence of allergy, and/or neurodevelopmental and autoimmune diagnoses in children born to anti-Ro antibody-positive mothers. METHODS:We conducted a cohort study of children born to anti-Ro antibody-positive mothers observed in the neonatal lupus erythematosus (NLE) clinic at The Hospital for Sick Children. Participants one year of age or older were invited to complete a health status questionnaire. Prevalence of allergic, neurodevelopmental, and autoimmune disease diagnoses was compared between the NLE cohort and the non-NLE population-based CHILD Cohort Study cohort. Descriptive statistics were used for demographics, NLE manifestations, and outcomes. Fisher's exact test compared the prevalence of diagnoses between subgroups. We tested the association between allergies and neurodevelopmental conditions and NLE with logistic regression models. A P-value < 0.006 was considered significant. RESULTS:We included 321 participants born to anti-Ro antibody-positive mothers. The median age at survey completion was six years, 51% of participants were female, and 50% (n = 162) had NLE. We found no significant difference in any disease prevalence between children with and without NLE manifestations (P = 0.57) or between children born to mothers with and without a rheumatic disease (P = 0.11). Disease prevalence was similar between the NLE and CHILD cohorts (allergic disease 30% vs 22% [P= 0.25], neurodevelopmental conditions 5% vs 2% [P = 0.45], autoimmune disease 4% vs 2% [P = 0.68]). CONCLUSION:In a large multiethnic cohort of infants born to anti-Ro antibody-positive mothers, there was no significant difference in the prevalence of allergic, neurodevelopmental, or autoimmune diseases between children with and without NLE or between those born to anti-Ro antibody-positive mothers and a population-based non-NLE cohort.

ObjectiveNeonatal lupus erythematosus (NLE) is a passively acquired autoimmune disease in infants born to anti-Ro and/or anti-La autoantibody-positive mothers. Genetics may affect NLE risk. We analyzed the genetics of infants and anti-Ro antibody-positive mothers, with NLE and NLE-specific manifestations.MethodsInfants and mothers from a tertiary care clinic underwent genotyping on the Global Screening Array. We created additive non-HLA and HLA polygenic risk scores (PRS) for systemic lupus erythematosus (SLE), from one of the largest genome-wide association studies. Outcomes were any NLE manifestations, cardiac NLE, and cutaneous NLE. We tested the association between SLE-PRS in the infant, mother, and the PRS difference between the mother and infant with NLE outcomes, in logistic regression and generalized linear mixed models (BonferroniP< 0.02). We also performed HLA-wide analyses for the outcomes (P< 5.00 × 10–8).ResultsThe study included 332 infants, 270 anti-Ro antibody-positive mothers, and 253 mother-infant pairs. A large proportion of mothers (40.4%) and infants (41.3%) were European, and 50% of infants were female. More than half of the infants had NLE (53%), including 7.2% with cardiac NLE and 11.7% with cutaneous NLE. We did not identify significant associations between infant PRS, maternal PRS, or maternal-infant PRS difference and any NLE outcomes. HLA-wide analyses did not identify NLE risk alleles.ConclusionIn a multiethnic cohort of infants and anti-Ro antibody-positive mothers, we did not identify a significant association between SLE genetics and risk of NLE outcomes.

PV107 / #499 Poster Topic:AS12 - Genetics, Epigenetics, Transcriptomics Lupus nephritis (LN) is one of the most common and severe manifestations of systemic lupus erythematosus (SLE). We performed genome-wide association studies (GWAS) for lupus nephritis and kidney function measures over time. We hypothesized that analyzing a person’s eGFR variability over time would be a good proxy for LN and improve power for detecting genetic loci for LN. We also used local ancestry estimation to facilitate inclusion of admixed individuals. We included SLE patients from several child and adult dedicated lupus databases and the Systemic Lupus International Collaborating Clinics (SLICC) cohort. All met American College of Rheumatology and/or SLICC SLE criteria and were genotyped on a multi-ethnic Illumina array. Ungenotyped SNPs were imputed to the Trans-Omics for Precision Medicine program (TopMed), and local ancestry of chromosomal information was estimated using RFMix and Tractor software. LN was defined by SLE criteria, with a subset confirmed by kidney biopsy. Kidney function (estimated glomerular filtration rate, eGFR) was calculated using the Schwartz formula for measures <18 years and CKD-EPI for >18 years of age. Wilcoxon rank-sum or Chi-square tests were used to compare characteristics between LN and Non-LN patients. We completed separate GWAS for the outcomes of LN, mean eGFR and eGFR variability over time (log of the mean absolute deviation from mean eGFR per participant), in marginal and multivariable-adjusted regression models with sex, site and local principal components using Regenie. Local ancestry analysis was restricted to individuals of European, African and East Asian ancestry using Tractor. We meta-analyzed ancestry-specific results with METAL software (significancep<5x10^-8). We studied 2981 individuals with SLE, 88% female, 46% of European ancestry, 27% childhood-onset SLE, and 45% with LN (Table). Kidney failure was observed in 25 patients over a median follow-up time of 8.9 years (IQR: 4.1,14.8). Within-person eGFR was similar between people with and without LN, but eGFR variability was significantly greater in people with LN (P-value= 2.2e-16). Variability was calculated using a median of 16 [IQR: 8,35] eGFR measurements per person. GWAS of LN did not identify a significant LN locus, yet GWAS of eGFR variability demonstrated a significant peak on chromosome 15, downstream ofSCH4and intronic toSECISBP2L(Figure). The variant was found in a genomic region of African ancestry. Table. Figure. We completed GWAS of LN, eGFR mean and variability over time, generating ancestry-specific estimates and identified a genome-wide significant locus for variability in measures of renal function over time, in a multiethnic cohort of children and adults with SLE. This locus was only found in an African ancestry portion of the genome. Variability in measures of renal function is correlated with LN, yet GWAS of LN did not identify significant loci. Future work includes repeating analyses to include all global ancestries, and to investigate the biologic link between the loci and LN.

BACKGROUND:Depressive and anxiety symptoms are common in childhood-onset systemic lupus erythematosus (cSLE), yet their etiology and course remain unclear. We investigated the frequency of depressive and anxiety symptoms longitudinally in youth with cSLE, and associated socio-demographic and disease factors.METHODS:Participants 8-18 years with cSLE completed baseline measures [demographic questionnaire, Center for Epidemiologic Studies Depression Scale for Children (CES-DC), Screen for Childhood Anxiety Related Disorders (SCARED), and psychiatric interview] and follow-up measures (CES-DC and SCARED) > 6 months later. Prevalence of clinically significant depressive (score >15 on CES-DC) or anxiety symptoms (score ≥25 on SCARED) was calculated at baseline and follow-up. Baseline psychiatric interview diagnoses were tabulated. Relationships between socio-demographics (neighborhood-level material deprivation, ethnic concentration, adverse childhood event history, psychiatric condition in a first-degree relative), disease-related factors (disease duration, major organ disease, disease activity, glucocorticoid use, comorbid medical condition) and baseline depressive and anxiety scores, were examined in linear regression models. Factors with univariate associations with p < 0.2 were included in multivariable adjusted models.RESULTS:At baseline, of 51 participants with a mean disease duration of 4.3 years (SD 2.7), 35% (n = 18) and 35% (n = 18) had clinically significant depressive and anxiety symptoms, respectively. Anxiety disorder was diagnosed by psychiatric interview in 14% (n = 7), depressive disorders in 6% (n = 3), and post-traumatic stress disorder in 4% (n = 2). Adverse childhood events and first-degree relative with psychiatric condition were present in 40% (n = 20) and 37% (n = 18), respectively. In multivariable regression analysis, baseline depressive symptoms were positively correlated with neighbourhood-level material deprivation (β = 4.2, 95% CI [1.0, 7.3], p = 0.01) and psychiatric condition in a first-degree relative (β = 7.3, 95% CI [2.2, 12.4], p = 0.006). No associations were found between baseline anxiety scores and patient factors. At a median follow-up of 13.5 months (IQR 10.5, 18) for CES-DC (n = 34) and SCARED (n = 44), depressive and anxiety symptoms were persistent (18%, n = 6; 16%, n = 7), and newly present (24%, n = 8; 16% n = 7) at follow-up.CONCLUSION:In this sample, depressive and anxiety symptoms were prevalent and persistent. Depressive symptoms correlated with neighborhood-level material deprivation, and family psychiatric history. These findings support routine psychosocial assessment in cSLE, and provision of appropriate resources.

Background Systemic lupus erythematosus (SLE) is a chronic autoimmune disease. Genetics play a role in SLE susceptibility, with >100 risk single nucleotide polymorphisms (SNPs) from genome wide association studies (GWAS). Approximately 20% of SLE patients have childhood- onset SLE (cSLE) diagnosed <18 years. These patients are at risk for reduced bone mineral density (BMD) due to disease activity and chronic glucocorticoid exposure. Our aim was to assess the genetic contribution to bone mineral density among a multi-ethnic cohort of patients with cSLE. Methods All patients were diagnosed and followed for cSLE at the SickKids Lupus Clinic. Patients were genotyped on the multiethnic Multiethnic Genotyping Array or the Infinium Global Screening Array. Those with baseline Lumbar Spine (LS) BMD dual-energy X-ray absorptiometry (DXA) scan were included in analysis. Baseline was defined as 1 month prior, or up to one year after cSLE diagnosis. Patients with bony abnormalities and with DXA scans due to medical conditions other than SLE were excluded. We extracted demographics, clinical features, and medication use from the Lupus database. The main outcome of interest was LS (L1-L4) BMD z scores. Two weighted polygenic risk scores (PRSs) were calculated. 1.) BMD PRS was calculated using alleles associated with low LS from the largest LS BMD meta-GWAS of BMD to date. 2.) SLE PRS was also calculated using one of the largest SLE GWAS. We regressed BMD and SLE PRSs with baseline BMD z-scores in linear models adjusted for sex, ancestry, glucocorticoid exposure, height percentile, and an indicator for lupus nephritis and/or neuropsychiatric lupus. Results Our study included 285 patients, 82% female, 30% of European and 28% of East Asian ancestry. The median age of cSLE diagnosis was 13.3 years [IQR 10.8, 15.1]. In univariate and multivariate adjusted models, a higher BMD PRS was significantly associated with low BMD z- score (β: -0.73; 95%CI: -1.30, -0.16; P = 0.01, multivariable model). Using steroids prior to DXA was significantly associated with low BMD at a univariate level but was not significant in the adjusted model. Height percentile was significantly associated with BMD z-score (β: 0.01; 95%CI: 0.01, 0.02; P=5.09e-10), yet the presence of LN and/or NPSLE was not (β: 0.06; 95%CI: 0.21, 0.33; P=0.67). Conclusions Our study found that a low-BMD PRS was significantly associated with lower LS BMD z-score in cSLE patients at baseline. BMD PRS may be used to stratify patients with cSLE who are at greatest risk of reduced BMD. We hope to expand this to long term LS BMD z-scores and explore BMD PRS predicts long term BMD z scores among cSLE patients. Lay Summary Systemic lupus erythematosus, commonly known as lupus is chronic, life-threatening autoimmune disease. Up to 20% of all people with lupus are diagnosed during childhood. Treatment for lupus involves long-term steroids which can have devastating impacts on children's bones. However, different people respond differently to steroid treatment, with some patients having more severe negative side effects than others. We aimed to explore the genetic basis of bone mineral density (BMD) in children and adolescents diagnosed with SLE. We calculated genetic risk scores for: 1. low bone density (BMD); 2. Lupus risk. We tested the association between these genetic risk scores and BMD in a multiethnic group of children and adolescents with lupus. We found that genetics for low bone density was significantly associated with lower bone density in these lupus patients within 1 year of lupus diagnosis. This was true even when we accounted for steroid exposure and the presence of kidney and/or brain involvement. Our work has the potential to identify lupus patients at high risk of developing low bone density.

OBJECTIVES Genome-wide association studies (GWAS) have identified loci associated with estimated glomerular filtration rate (eGFR). Few lupus nephritis (LN) risk loci have been identified to date. We tested the association of systemic lupus erythematosus (SLE) and eGFR polygenic risk scores (PRS) with repeated eGFR measures from children and adults with SLE. METHODS Patients from two tertiary care lupus clinics that met ≥4 ACR and/or SLICC criteria for SLE were genotyped on the Illumina MEGA or Omni1-Quad arrays. PRSs were calculated for SLE and eGFR, using published weighted GWA-significant alleles. eGFR was calculated using the CKD-EPI and Schwartz equations. We tested the effect of eGFR- and SLE-PRSs on eGFR mean and variance, adjusting for age at diagnosis, sex, ancestry, follow-up time, and clinical event flags. RESULTS We included 1158 SLE patients (37% biopsy-confirmed LN) with 36,733 eGFR measures over a median of 7.6 years (IQR:3.9-15.3). LN was associated with lower within-person mean eGFR (LN: 93.8 [SD 26.4] vs. non-LN: 101.6 [SD 17.7] mL/min per 1.73 m2; P<0.0001) and higher variance (LN median: 157.0 [IQR:89.5, 268.9] vs. non-LN median: 84.9 [IQR:46.9, 138.2] (mL/min per 1.73 m2)2; P <0.0001). Increasing SLE-PRSs were associated with lower mean eGFR and greater variance, while increasing eGFR-PRS was associated with increased eGFR mean and variance. CONCLUSION We observed significant associations between SLE and eGFR PRSs and repeated eGFR measurements, in a large cohort of children and adults with SLE. Longitudinal eGFR may serve as a powerful alternative outcome to LN categories for discovery of LN risk loci.

Objectives Genetics plays an important role in SLE risk, as well as osteonecrosis (ON), a significant and often debilitating complication of SLE. We aimed to identify genetic risk loci for ON in people with childhood-onset (cSLE) and adult-onset (aSLE) SLE. Methods We enrolled participants from two tertiary care centres who met classification criteria for SLE. Participants had prospectively collected clinical data and were genotyped on a multiethnic array. Un-genotyped single nucleotide polymorphisms (SNPs) were imputed, and ancestry was inferred using principal components (PCs). Our outcome was symptomatic ON confirmed by imaging. We completed time-to-ON and logistic regression of ON genome-wide association studies (GWASs) with covariates for sex, age of SLE diagnosis, five PCs for ancestry, corticosteroid use and selected SLE manifestations. We conducted separate analyses for cSLE and aSLE and meta-analysed results using inverse-variance weighting. Genome-wide significance was P < 5 x 10(-8). Results The study included 940 participants with SLE, 87% female and 56% with cSLE. ON was present in 7.6% (n = 71). Median age of SLE diagnosis was 16.9 years (interquartile range [IQR]: 13.5, 29.3), with median follow-up of 8.0 years (IQR: 4.2, 15.7). Meta-GWAS of cSLE and aSLE time-to-ON of 4 431 911 SNPs identified a significant Chr.2 SNP, rs34118383 (minor allele frequency = 0.18), intronic to WIPF1 (hazard ratio = 3.2 [95% CI: 2.2, 4.8]; P = 1.0 x 10(-8)). Conclusion We identified an intronic WIPF1 variant associated with a 3.2 times increased hazard for ON (95% CI: 2.2, 4.8; P = 1.0 x 10(-8)) during SLE follow-up, independent of corticosteroid exposure. The effect of the SNP on time-to-ON was similar in cSLE and aSLE. This novel discovery represents a potential ON risk locus. Our results warrant replication.

Objective Genetics play an important role in systemic lupus erythematosus (SLE) pathogenesis. We calculated the prevalence of rare variants in known monogenic lupus genes among children suspected of monogenic lupus. Methods We completed paired-end genome-wide sequencing (whole genome sequencing [WGS] or whole exome sequencing) in patients suspected of monogenic lupus, and focused on 36 monogenic lupus genes. We prioritized rare (minor allele frequency < 1%) exonic, nonsynonymous, and splice variants with predicted pathogenicity classified as deleterious variants (Combined Annotation Dependent Depletion [CADD], PolyPhen2, and Sorting Intolerant From Tolerant [SIFT] scores). Additional filtering restricted to predicted damaging variants by considering reported zygosity. In those with WGS (n = 69), we examined copy number variants (CNVs) > 1 kb in size. We created additive non-HLA and HLA SLE genetic risk scores (GRSs) using common SLE-risk single-nucleotide polymorphisms. We tested the relationship between SLE GRSs and the number of rare variants with multivariate logistic models, adjusted for sex, ancestry, and age of diagnosis. Results The cohort included 71 patients, 80% female, with a mean age at diagnosis of 8.9 (SD 3.2) years. We identified predicted damaging variants in 9 (13%) patients who were significantly younger at diagnosis compared to those without a predicted damaging variant (6.8 [SD 2.1] years vs 9.2 [SD 3.2] years, P = 0.01). We did not identify damaging CNVs. There was no significant association between non-HLA or HLA SLE GRSs and the odds of carrying ≥ 1 rare variant in multivariate analyses. Conclusion In a cohort of patients with suspected monogenic lupus who underwent genome-wide sequencing, 13% carried rare predicted damaging variants for monogenic lupus. Additional studies are needed to validate our findings.

ObjectiveMacrophage activation syndrome (MAS), a life-threatening complication of systemic lupus erythematosus (SLE), resembles familial hemophagocytic lymphohistiocytosis (HLH), an inherited disorder of hyperinflammation. We compared the proportion of patients with childhood-onset SLE (cSLE) with and without MAS who carried low-frequency HLH nonsynonymous variants.MethodsWe enrolled patients from the Lupus Clinic at SickKids, Toronto. Demographic and clinical features were extracted from the SLE database and ancestry was genetically inferred using multiethnic genotyping array data. Patients with MAS (based on expert diagnosis) underwent either paired-end whole-exome sequencing (WES; read depth: 70-118X) or whole-genome sequencing (WGS). Patients without MAS had WGS (read depth: 37-40X). In 16 HLH genes, we prioritized low-frequency (minor allele frequency [MAF] < 0.05) exonic nonsynonymous variants. We compared the proportion of patients with and without MAS carrying HLH variants (Fisher exact test,P< 0.05). MAFs were compared to an ancestrally matched general population (Trans-Omics for Precision Medicine [TOPMed] and Genome Aggregation Database [gnomAD]).ResultsThe study included 81 patients with cSLE, 19 of whom had MAS. We identified 47 unique low-frequency nonsynonymous HLH variants. There was no difference in the proportion of patients with and without MAS carrying ≥ 1 HLH variants (37% vs 47%,P= 0.44). The MAS cohort did not carry more HLH variants when compared to an ancestrally matched general population.ConclusionIn a single-center multiethnic cSLE cohort, we found no difference in the proportion of patients with MAS carrying nonsynonymous HLH genetic variants compared to patients without MAS. To our knowledge, this is the first study to examine the frequency of HLH genetic variants in relation to MAS among patients with cSLE. Future studies are required to validate our findings.