Association of the IFIH1-GCA-KCNH7 chromosomal region with rheumatoid arthritis.

Annals of the rheumatic diseases (Impact Factor: 8.11). 02/2008; 67(1):137-8. DOI: 10.1136/ard.2007.073213
Source: PubMed
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    ABSTRACT: Identification of genetic variants that influence bipolar I disorder (BPD-I) through genome-wide association (GWA) studies are limited in Asian populations. The current study aimed to identify novel common variants for BPD-I in an ethnically homogeneous Taiwanese sample using a multi-stage GWA study design. At the discovery stage, 200 BPD-I patients and 200 controls combined to form 16 pools were genotyped with 1 million markers. Utilizing a newly developed rank-based method, top-ranked markers were selected. After validation with individual genotyping, a fine-mapping association study was conducted to identify associated loci using 240 patients and 240 controls. At the last stage, independent samples were collected (351 cases and 341 controls) for replication. Among the top-ranked markers from the discovery stage, eight genes and 15 individual SNPs were evaluated in the fine-mapping stage. At this stage, rs7619173, which is not in a gene coding region, showed the most significant association (P=2*10(-5)) with BPD-I. Four genes had empirical p-values <0.05, including KCNH7 (P=0.0047), MYST4 (P=0.0047), NRXN3 (P=0.0095), and SEMA3D (P=0.037). For markers genotyped in replication samples, rs7619173 exhibited a significant association (Pcombined=2*10(-4)) after multiple testing correction, while markers rs11001178 (MYST4) and rs2217887 (NRXN3) showed weak associations (Pcombined=0.02) with BPD-I. A multi-stage GWA design has the potential to uncover the underlying pathogenesis of a complex trait. Findings in the present study highlight three loci that warrant further investigation for bipolar.
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    ABSTRACT: Abstract Published data on the association between the IFIH1 rs1990760 polymorphism and multiple autoimmune diseases are controversial and inconclusive. To more precisely estimate the association between the IFIH1 rs1990760 polymorphism and susceptibility to autoimmune diseases, a meta-analysis was conducted. Studies examining the association of the IFIH1 rs1990760 polymorphism with autoimmune diseases were exhaustively searched using PubMed, Web of Science and a review of the references. A total of 19 studies with 26 comparisons including 8 type 1 diabetes (T1D), 5 systemic lupus erythematosus (SLE), 5 Graves' disease (GD), 2 multiple scleorosis (MS), 2 rheumatoid arthritis (RA), 2 Hashimoto's thyroiditis (HT), 2 autoimmune Addison's disease (AAD) were available for this meta-analysis. Meta-analysis was performed for genotype T/T + T/C (dominant model), genotype T/T (recessive model) and T-allele in fixed or random-effects models. The overall odds ratios (ORs) and 95% confidence intervals (CIs) for T-allele were T1D (OR = 1.184, 95% CI = 1.142-1.229), SLE (OR = 1.143, 95% CI = 1.073-1.217), MS (OR = 1.181, 95% CI = 1.062-1.313) and RA (OR = 1.115, 95% CI = 1.004-1.239), respectively. For T1D and SLE, significant association was observed in the population of European ancestry, but not in the Asian population. This meta-analysis demonstrates that the IFIH1 rs1990760 T-allele confers susceptibility to T1D, SLE, MS and RA and suggests that the IFIH1 rs1990760 polymorphism might have no effect on GD and AAD. Our result provides further evidence for the notion of common gene underlying multiple autoimmune diseases.
    Autoimmunity 06/2013; · 2.77 Impact Factor
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    ABSTRACT: Abstract The Thr allele at the Thr946Ala non-synonymous single-nucleotide polymorphism (nsSNP) in the IFIH1 gene confers risk for type 1 diabetes (T1D). IFIH1 binds viral double-stranded RNA (dsRNA), inducing a type I interferon (IFN) response. Reports of this nsSNP's role in IFIH1 expression regulation have produced conflicting results and a study evaluating transfected Thr946Ala protein alleles in an artificial system overexpressing IFIH1 shows that the SNP does not affect IFH1 function. In this study, we examine the effects of the Thr946Ala polymorphism on IFN-α response in a cell line that endogenously expresses physiological levels of IFIH1. Eleven lymphoblastoid cell lines (LCLs) homozygous for the major predisposing allele (Thr/Thr) and 6 LCLs homozygous for the minor protective allele (Ala/Ala) were electroporated with the viral dsRNA mimic, poly I:C, in three independent experiments. Media were collected 24 hours later and measured for IFN-α production by ELISA. Basal IFN response is minimal in mock-transfected cells from both genotypes and increases by about 8-fold in cells treated with poly I:C. LCLs with the Ala/Ala genotype have slightly higher IFN-α levels than their Thr/Thr counterparts but this did not reach statistical significance because of the large variability of the IFN response, due mostly to two high outliers (biological, not technical). A larger sample size would be needed to determine whether the Thr946Ala SNP affects the poly I:C-driven IFN-α response. Additionally, the possibility that this nsSNP recognizes viral dsRNA specificities cannot be ruled out. Thus, the mechanism of the observed association of this SNP with T1D remains to be determined.
    Autoimmunity 10/2013; · 2.77 Impact Factor