| 1. |
- Chung, Sharon A, et al.
(författare)
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European population substructure is associated with mucocutaneous manifestations and autoantibody production in systemic lupus erythematosus
- 2009
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Ingår i: Arthritis and Rheumatism. - : Wiley. - 0004-3591 .- 1529-0131. ; 60:8, s. 2448-2456
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To determine whether genetic substructure in European-derived populations is associated with specific manifestations of systemic lupus erythematosus (SLE), including mucocutaneous phenotypes, autoantibody production, and renal disease. METHODS: SLE patients of European descent (n=1,754) from 8 case collections were genotyped for >1,400 ancestry informative markers that define a north-south gradient of European substructure. Using the Structure program, each SLE patient was characterized in terms of percent Northern (versus percent Southern) European ancestry based on these genetic markers. Nonparametric methods, including tests for trend, were used to identify associations between Northern European ancestry and specific SLE manifestations. RESULTS: In multivariate analyses, increasing levels of Northern European ancestry were significantly associated with photosensitivity (Ptrend=0.0021, odds ratio for highest quartile of Northern European ancestry versus lowest quartile [ORhigh-low] 1.64, 95% confidence interval [95% CI] 1.13-2.35) and discoid rash (Ptrend=0.014, ORhigh-low 1.93, 95% CI 0.98-3.83). In contrast, increasing levels of Northern European ancestry had a protective effect against the production of anticardiolipin autoantibodies (Ptrend=1.6x10(-4), ORhigh-low 0.46, 95% CI 0.30-0.69) and anti-double-stranded DNA autoantibodies (Ptrend=0.017, ORhigh-low 0.67, 95% CI 0.46-0.96). CONCLUSION: This study demonstrates that specific SLE manifestations vary according to Northern versus Southern European ancestry. Thus, genetic ancestry may contribute to the clinical heterogeneity and variation in disease outcomes among SLE patients of European descent. Moreover, these results suggest that genetic studies of SLE subphenotypes will need to carefully address issues of population substructure based on genetic ancestry.
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| 2. |
- Gateva, Vesela, et al.
(författare)
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A large-scale replication study identifies TNIP1, PRDM1, JAZF1, UHRF1BP1 and IL10 as risk loci for systemic lupus erythematosus
- 2009
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 41:11, s. 1228-1233
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Tidskriftsartikel (refereegranskat)abstract
- Genome-wide association studies have recently identified at least 15 susceptibility loci for systemic lupus erythematosus (SLE). To confirm additional risk loci, we selected SNPs from 2,466 regions that showed nominal evidence of association to SLE (P < 0.05) in a genome-wide study and genotyped them in an independent sample of 1,963 cases and 4,329 controls. This replication effort identified five new SLE susceptibility loci (P < 5 x 10(-8)): TNIP1 (odds ratio (OR) = 1.27), PRDM1 (OR = 1.20), JAZF1 (OR = 1.20), UHRF1BP1 (OR = 1.17) and IL10 (OR = 1.19). We identified 21 additional candidate loci with P< or = 1 x 10(-5). A candidate screen of alleles previously associated with other autoimmune diseases suggested five loci (P < 1 x 10(-3)) that may contribute to SLE: IFIH1, CFB, CLEC16A, IL12B and SH2B3. These results expand the number of confirmed and candidate SLE susceptibility loci and implicate several key immunologic pathways in SLE pathogenesis.
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| 3. |
- Graham, R. Robert, et al.
(författare)
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Three functional variants of IFN regulatory factor 5 (IRF5) define risk and protective haplotypes for human lupus
- 2007
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 104:16, s. 6758-6763
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Tidskriftsartikel (refereegranskat)abstract
- Systematic genome-wide studies to map genomic regions associated with human diseases are becoming more practical. Increasingly, efforts will be focused on the identification of the specific functional variants responsible for the disease. The challenges of identifying causal variants include the need for complete ascertainment of genetic variants and the need to consider the possibility of multiple causal alleles. We recently reported that risk of systemic lupus erythematosus (SLE) is strongly associated with a common SNP in IFN regulatory factor 5 (IRF5), and that this variant altered spicing in a way that might provide a functional explanation for the reproducible association to SLE risk. Here, by resequencing and genotyping in patients with SLE, we find evidence for three functional alleles of IRF5: the previously described exon 1B splice site variant, a 30-bp in-frame insertion/deletion variant of exon 6 that alters a proline-, glutamic acid-, serine- and threonine-rich domain region, and a variant in a conserved polyA+ signal sequence that alters the length of the 3' UTR and stability of IRF5 mRNAs. Haplotypes of these three variants define at least three distinct levels of risk to SLE. Understanding how combinations of variants influence IRF5 function may offer etiological and therapeutic insights in SLE; more generally, IRF5 and SLE illustrates how multiple common variants of the same gene can together influence risk of common disease.
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| 4. |
- Hom, Geoffrey, et al.
(författare)
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Association of systemic lupus erythematosus with C8orf13-BLK and ITGAM-ITGAX.
- 2008
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Ingår i: New England Journal of Medicine. - : Massachusetts Medical Society. - 0028-4793 .- 1533-4406. ; 358:9, s. 900-909
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Systemic lupus erythematosus (SLE) is a clinically heterogeneous disease in which the risk of disease is influenced by complex genetic and environmental contributions. Alleles of HLA-DRB1, IRF5, and STAT4are established susceptibility genes; there is strong evidence for the existence of additional risk loci.METHODS: We genotyped more than 500,000 single-nucleotide polymorphisms (SNPs) in DNA samples from 1311 case subjects with SLE and 1783 control subjects; all subjects were North Americans of European descent. Genotypes from 1557 additional control subjects were obtained from public data repositories. We measured the association between the SNPs and SLE after applying strict quality-control filters to reduce technical artifacts and to correct for the presence of population stratification. Replication of the top loci was performed in 793 case subjects and 857 control subjects from Sweden.RESULTS: Genetic variation in the region upstream from the transcription initiation site of the gene encoding B lymphoid tyrosine kinase (BLK) and C8orf13 (chromosome 8p23.1) was associated with disease risk in both the U.S. and Swedish case–control series (rs13277113; odds ratio, 1.39; P=1×10−10) and also with altered levels of messenger RNA in B-cell lines. In addition, variants on chromosome 16p11.22, near the genes encoding integrin alpha M (ITGAM, or CD11b) and integrin alpha X (ITGAX), were associated with SLE in the combined sample (rs11574637; odds ratio, 1.33; P=3×10−11).
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| 5. |
- Namjou, Bahram, et al.
(författare)
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High-density genotyping of STAT4 reveals multiple haplotypic associations with systemic lupus erythematosus in different racial groups
- 2009
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Ingår i: Arthritis and Rheumatism. - : Wiley. - 0004-3591 .- 1529-0131. ; 60:4, s. 1085-1095
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Systemic lupus erythematosus (SLE) is the prototypical systemic autoimmune disorder, with complex etiology and a strong genetic component. Recently, gene products involved in the interferon pathway have been under intense investigation in terms of the pathogenesis of SLE. STAT-1 and STAT-4 are transcription factors that play key roles in the interferon and Th1 signaling pathways, making them attractive candidates for involvement in SLE susceptibility. METHODS: Fifty-six single-nucleotide polymorphisms (SNPs) across STAT1 and STAT4 on chromosome 2 were genotyped using the Illumina platform, as part of an extensive association study in a large collection of 9,923 lupus patients and control subjects from different racial groups. DNA samples were obtained from the peripheral blood of patients with SLE and control subjects. Principal components analyses and population-based case-control association analyses were performed, and the P values, false discovery rate q values, and odds ratios with 95% confidence intervals were calculated. RESULTS: We observed strong genetic associations with SLE and multiple SNPs located within STAT4 in different ethnic groups (Fisher's combined P = 7.02 x 10(-25)). In addition to strongly confirming the previously reported association in the third intronic region of this gene, we identified additional haplotypic association across STAT4 and, in particular, a common risk haplotype that is found in multiple racial groups. In contrast, only a relatively weak suggestive association was observed with STAT1, probably due to its proximity to STAT4. CONCLUSION: Our findings indicate that STAT4 is likely to be a crucial component in SLE pathogenesis in multiple racial groups. Knowledge of the functional effects of this association, when they are revealed, might improve our understanding of the disease and provide new therapeutic targets.
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| 6. |
- Petri, Michelle, et al.
(författare)
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Systemic lupus international collaborating clinics renal activity/response exercise - Development of a renal activity score and renal response index
- 2008
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Ingår i: Arthritis and Rheumatism. - : Wiley. - 1529-0131 .- 0004-3591. ; 58:6, s. 1784-1788
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Tidskriftsartikel (refereegranskat)abstract
- Objective. To develop a measure of renal activity in systemic lupus erythematosus and use it to develop a renal response index. Methods. Abstracted data from the medical records of 215 patients with lupus nephritis were sent to 8 nephrologists and 29 rheumatologists for rating. Seven nephrologists and 22 rheumatologists completed the ratings. Each physician rated each patient visit with respect to renal disease activity (none, mild, moderate, or severe). Using the most commonly selected rating for each patient as the gold standard, stepwise regression modeling was performed to identify the variables most related to renal disease activity, and these variables were then used to create an activity score. This activity score could then be applied to 2 consecutive visits to define a renal response index. Results. The renal activity score was computed as follows: proteinuria 0.5-1 gm/day (3 points), proteinuria >1-3 gm/day (5 points), proteinuria >3 gm/day (11 points), urine red blood cell count > 10/high-power field (3 points), and urine white blood cell count >10/high-power field (I point). The chance-adjusted agreement between the renal response index derived from the activity score applied to the paired visits and the plurality physician response rating was 0.69 (95% confidence interval 0.59-0.79). Conclusion. Ratings derived from this index for rating of renal response showed reasonable agreement with physician ratings in a pilot study. The index will require further refinement, testing, and validation. A data-driven approach to create renal activity and renal response indices will be useful in both clinical care and research settings.
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| 7. |
- Webb, Ryan, et al.
(författare)
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A polymorphism within IL21R confers risk for systemic lupus erythematosus
- 2009
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Ingår i: Arthritis and Rheumatism. - : Wiley. - 0004-3591 .- 1529-0131. ; 60:8, s. 2402-2407
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Interleukin-21 (IL-21) is a member of the type I cytokine superfamily that has a variety of effects on the immune system, including B cell activation, plasma cell differentiation, and immunoglobulin production. The expression of IL-21 receptor (IL-21R) is reduced in the B cells of patients with systemic lupus erythematosus (SLE), while serum IL-21 levels are increased both in lupus patients and in some murine lupus models. We recently reported that polymorphisms within the IL21 gene are associated with increased susceptibility to SLE. The aim of this study was to examine the genetic association between single-nucleotide polymorphisms (SNPs) within IL21R and SLE. METHODS: We genotyped 17 SNPs in the IL21R gene in 2 large cohorts of lupus patients (a European-derived cohort and a Hispanic cohort) and in ethnically matched healthy controls. RESULTS: We identified and confirmed the association between rs3093301 within the IL21R gene and SLE in the 2 cohorts (meta-analysis odds ratio 1.16 [95% confidence interval 1.08-1.25], P=1.0x10(-4)). CONCLUSION: Our findings indicate that IL21R is a novel susceptibility gene for SLE.
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| 8. |
- Webb, Ryan, et al.
(författare)
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Variants within MECP2, a key transcription regulator, are associated with increased susceptibility to lupus and differential gene expression in patients with systemic lupus erythematosus
- 2009
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Ingår i: Arthritis and Rheumatism. - : Wiley. - 0004-3591 .- 1529-0131. ; 60:4, s. 1076-1084
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Both genetic and epigenetic factors play an important role in the pathogenesis of lupus. The aim of this study was to examine methyl-CpG-binding protein 2 gene (MECP2) polymorphisms in a large cohort of patients with lupus and control subjects, and to determine the functional consequences of the lupus-associated MECP2 haplotype. METHODS: We genotyped 18 single-nucleotide polymorphisms within MECP2, located on chromosome Xq28, in a large cohort of patients with lupus and control subjects of European descent. We studied the functional effects of the lupus-associated MECP2 haplotype by determining gene expression profiles in B cell lines in female lupus patients with and those without the lupus-associated MECP2 risk haplotype. RESULTS: We confirmed, replicated, and extended the genetic association between lupus and genetic markers within MECP2 in a large independent cohort of lupus patients and control subjects of European descent (odds ratio 1.35, P = 6.65 x 10(-11)). MECP2 is a dichotomous transcription regulator that either activates or represses gene expression. We identified 128 genes that are differentially expressed in lupus patients with the disease-associated MECP2 haplotype; most ( approximately 81%) were up-regulated. Genes that were up-regulated had significantly more CpG islands in their promoter regions compared with genes that were down-regulated. Gene ontology analysis using the differentially expressed genes revealed significant association with epigenetic regulatory mechanisms, suggesting that these genes are targets for MECP2 regulation in B cells. Furthermore, at least 13 of the 104 up-regulated genes are regulated by interferon. The disease-risk MECP2 haplotype was associated with increased expression of the MECP2 transcription coactivator CREB1 and decreased expression of the corepressor histone deacetylase 1. CONCLUSION: Polymorphism in the MECP2 locus is associated with lupus and, at least in part, contributes to the interferon signature observed in lupus patients.
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