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ObjectiveThe increased risk of thrombosis in systemic lupus erythematosus (SLE) may be partially explained by interrelated genetic pathways for thrombosis and SLE. The present study was undertaken to investigate whether 33 established and novel single-nucleotide polymorphisms (SNPs) in 20 genes involved in hemostasis pathways that have been associated with deep venous thrombosis (DVT) in the general population are risk factors for SLE among Asian subjects.MethodsPatients in the discovery cohort were enrolled in 1 of 2 North American SLE cohorts. Patients in the replication cohort were enrolled in 1 of 4 Asian or 2 North American cohorts. We first genotyped 263 Asian patients with SLE and 357 healthy Asian control subjects for 33 SNPs in the discovery phase, and then genotyped 5 SNPs in up to an additional 1,496 patients and 993 controls in the replication phase. Patients were compared to controls for bivariate association with minor alleles. Principal components analysis was used to control for intra-Asian ancestry in the replication cohort.ResultsTwo genetic variants in the gene VKORC1 were highly significant in both the discovery and replication cohorts: rs9934438 (in the discovery cohort, odds ratio [OR] 2.45, P=2×10(-9); in the replication cohort, OR 1.54, P=4×10(-6)) and rs9923231 (in the discovery cohort, OR 2.40, P=6×10(-9); in the replication cohort, OR 1.53, P=5×10(-6)). These associations were significant in the replication cohort after adjustment for intra-Asian ancestry: for rs9934438, OR 1.34, P=0.0029; for rs9923231, OR 1.34, P=0.0032.ConclusionGenetic variants in VKORC1, which are involved in vitamin K reduction and associated with DVT, correlate with SLE development in Asian subjects. These results suggest that there may be intersecting genetic pathways for the development of SLE and thrombosis.

ObjectiveThrombosis is a serious complication of systemic lupus erythematosus (SLE). We investigated whether genetic variants implicated in thrombosis pathways are associated with thrombosis among 2 ethnically diverse SLE cohorts.MethodsOur discovery cohort consisted of 1698 patients with SLE enrolled in the University of California, San Francisco, Lupus Genetics Project and our replication cohort included 1361 patients with SLE enrolled in the PROFILE cohort. Patients fulfilled American College of Rheumatology SLE criteria, and data relevant to thrombosis were available. Thirty-three single nucleotide polymorphisms (SNP) previously shown to be associated with risk of deep venous thrombosis in the general population or implicated in thrombosis pathways were genotyped and tested for association with thrombosis in bivariate allelic analyses. SNP with p < 0.1 in the bivariate analyses were further tested in multivariable logistic regression models adjusted for age, sex, disease duration, antiphospholipid antibody status, smoking, nephritis, and medications.ResultsIn the discovery cohort, 23% of patients with SLE experienced a thrombotic event. SNP in the following genes demonstrated association with thrombosis risk overall in the discovery or replication cohorts and were assessed using metaanalytic methods: factor V Leiden (FVL) rs6025 (OR 1.85, p = 0.02) and methylenetetrahydrofolate reductase (MTHFR) rs1801133 (OR 0.75, p = 0.04) in whites, and fibrinogen gamma (FGG) rs2066865 (OR 1.91, p = 0.01) in Hispanic Americans. SNP in these genes showed association with venous thrombosis risk in whites: MTHFR rs1801131 (OR 1.51, p = 0.01), MTHFR rs1801133 (OR 0.70, p = 0.04), FVL rs6025 (OR 2.69, p = 0.002), and FGG rs2066865 (OR 1.49, p = 0.02) in whites. A SNP in FGG rs2066865 (OR 2.19, p = 0.003) demonstrated association with arterial thrombosis risk in Hispanics.ConclusionOur results implicate specific genetic risk factors for thrombosis in patients with SLE and suggest that genetic risk for thrombosis differs across ethnic groups.

We conducted a genome-wide association study of rheumatoid arthritis in 2,418 cases and 4,504 controls from North America and identified an association at the REL locus, encoding c-Rel, on chromosome 2p13 (rs13031237, P = 6.01 x 10(-10)). Replication in independent case-control datasets comprising 2,604 cases and 2,882 controls confirmed this association, yielding an allelic OR = 1.25 (P = 3.08 x 10(-14)) for marker rs13031237 and an allelic OR = 1.21 (P = 2.60 x 10(-11)) for marker rs13017599 in the combined dataset. The combined dataset also provides definitive support for associations at both CTLA4 (rs231735; OR = 0.85; P = 6.25 x 10(-9)) and BLK (rs2736340; OR = 1.19; P = 5.69 x 10(-9)). c-Rel is an NF-kappaB family member with distinct functional properties in hematopoietic cells, and its association with rheumatoid arthritis suggests disease pathways that involve other recently identified rheumatoid arthritis susceptibility genes including CD40, TRAF1, TNFAIP3 and PRKCQ.

We conducted a genome-wide association study of rheumatoid arthritis in 2,418 cases and 4,504 controls from North America and identified an association at the REL locus, encoding c-Rel, on chromosome 2p13 (rs13031237, P = 6.01 x 10(-10)). Replication in independent case-control datasets comprising 2,604 cases and 2,882 controls confirmed this association, yielding an allelic OR = 1.25 (P = 3.08 x 10(-14)) for marker rs13031237 and an allelic OR = 1.21 (P = 2.60 x 10(-11)) for marker rs13017599 in the combined dataset. The combined dataset also provides definitive support for associations at both CTLA4 (rs231735; OR = 0.85; P = 6.25 x 10(-9)) and BLK (rs2736340; OR = 1.19; P = 5.69 x 10(-9)). c-Rel is an NF-kappaB family member with distinct functional properties in hematopoietic cells, and its association with rheumatoid arthritis suggests disease pathways that involve other recently identified rheumatoid arthritis susceptibility genes including CD40, TRAF1, TNFAIP3 and PRKCQ.

Psoriasis is a common immune-mediated disorder that affects the skin, nails and joints. To identify psoriasis susceptibility loci, we genotyped 438,670 SNPs in 1,409 psoriasis cases and 1,436 controls of European ancestry. We followed up 21 promising SNPs in 5,048 psoriasis cases and 5,041 controls. Our results provide strong support for the association of at least seven genetic loci and psoriasis (each with combined P < 5 x 10(-8)). Loci with confirmed association include HLA-C, three genes involved in IL-23 signaling (IL23A, IL23R, IL12B), two genes that act downstream of TNF-alpha and regulate NF-kappaB signaling (TNIP1, TNFAIP3) and two genes involved in the modulation of Th2 immune responses (IL4, IL13). Although the proteins encoded in these loci are known to interact biologically, we found no evidence for epistasis between associated SNPs. Our results expand the catalog of genetic loci implicated in psoriasis susceptibility and suggest priority targets for study in other auto-immune disorders.

Psoriasis is a common immune-mediated disorder that affects the skin, nails and joints. To identify psoriasis susceptibility loci, we genotyped 438,670 SNPs in 1,409 psoriasis cases and 1,436 controls of European ancestry. We followed up 21 promising SNPs in 5,048 psoriasis cases and 5,041 controls. Our results provide strong support for the association of at least seven genetic loci and psoriasis (each with combined P < 5 x 10(-8)). Loci with confirmed association include HLA-C, three genes involved in IL-23 signaling (IL23A, IL23R, IL12B), two genes that act downstream of TNF-alpha and regulate NF-kappaB signaling (TNIP1, TNFAIP3) and two genes involved in the modulation of Th2 immune responses (IL4, IL13). Although the proteins encoded in these loci are known to interact biologically, we found no evidence for epistasis between associated SNPs. Our results expand the catalog of genetic loci implicated in psoriasis susceptibility and suggest priority targets for study in other auto-immune disorders.

Rheumatoid arthritis (RA) is a chronic, systemic autoimmune disease affecting both joints and extra-articular tissues. Although some genetic risk factors for RA are well-established, most notably HLA-DRB1 and PTPN22, these markers do not fully account for the observed heritability. To identify additional susceptibility loci, we carried out a multi-tiered, case-control association study, genotyping 25,966 putative functional SNPs in 475 white North American RA patients and 475 matched controls. Significant markers were genotyped in two additional, independent, white case-control sample sets (661 cases/1322 controls from North America and 596 cases/705 controls from The Netherlands) identifying a SNP, rs1953126, on chromosome 9q33.2 that was significantly associated with RA (OR(common) = 1.28, trend P(comb) = 1.45E-06). Through a comprehensive fine-scale-mapping SNP-selection procedure, 137 additional SNPs in a 668 kb region from MEGF9 to STOM on 9q33.2 were chosen for follow-up genotyping in a staged-approach. Significant single marker results (P(comb) 5.41E-09). The observed association patterns for these SNPs had heightened statistical significance and a higher degree of consistency across sample sets. In addition, the allele frequencies for these SNPs displayed reduced variability between control groups when compared to other SNPs. Lastly, in combination with the other two known genetic risk factors, HLA-DRB1 and PTPN22, the variants reported here generate more than a 45-fold RA-risk differential.

Background Rheumatoid arthritis (RA) is a chronic autoimmune disorder affecting ~1% of the population. The disease results from the interplay between an individual's genetic background and unknown environmental triggers. Although [...]

A multitiered, case-control association study of psoriasis is performed in three independent sample sets of white North American individuals which provides statistical support for two psoriasis-susceptibility loci one in Sq31.1-q33.1 and the other in 1p31.3. Preliminary analyses suggest that the combination of risk and protective haplotypes at both loci can lead to a more than threefold differential risk for disease.

A possible link between a gene on chromosome 19 and multiple sclerosis (MS) has been identified. Researchers found the link after performing genetic analysis on 120 Caucasian MS patients and 32 Chinese MS patients. Both groups were compared with similar groups that did not have MS. A strong link was found on chromosome 19q13.2, but it was not due to the apolipoprotein E (APOE) gene, which is at that location. Links were also found to the HLA DRB1*1501, DQA1*0102, and DQB1*0602 genes, which are on chromosome 6p21.3. No link was found to the myelin basic protein (MBP) gene., Context.--Susceptibility to multiple sclerosis (MS) involves a genetically complex autoimmune component. However, except for genes in the HLA system, specific susceptibility loci are unknown or unconfirmed. Objective.--To investigate several loci spanning 3 candidate regions for a role in multiple sclerosis (MS) susceptibility in 2 ethnic groups using both single-locus and haplotype analyses. The 3 regions include HLA on chromosome 6p21.3, APOE on chromosome 19q13.2, and MBP (myelin basic protein) on chromosome 18q23. Design.--Case-control association testing. Subjects.--A total of 120 Caucasian patients with MS and 107 unrelated control individuals from California, and 32 patients and 32 unrelated control individuals from Beijing, China. All patients with MS were diagnosed as having clinically definite disease according to published criteria. Main Outcome Measures.--[chi square] Testing of loci and individual alleles and haplotypes. Haplotype frequencies were estimated with standard maximum likelihood methods. Results.--The HLA effect is due to the class 11 DR2 haplotype, DRB1*1501-DQA1 *0102-DRB1 *0602; contributions to MS susceptibility from additional DRB1-DQB1 alleles or other HLA region loci were not observed. Variation within the MBP locus on chromosome 18q23 showed no effect in MS. The distribution of haplotypes from 5 loci within the chromosome 19q13.2 region, including D19S178, D19S574, APOE, APOC2, and D19S219, differed between patient and control samples. D19S574 showed a significant effect (P=.015) in Caucasian patients with MS due to the increased frequency of a single allele (P=.002). The APOE variation, prominent in other neurological diseases, showed no influence on MS susceptibility, despite its location within the chromosome 19q13.2 region. Interaction effects between DR2 and chromosome 19q13.2 or MBP in MS susceptibility were not apparent. Conclusions.--The significant chromosome 19q13.2 single-locus and multilocus haplotype associations with MS in Caucasian and Chinese patient samples indicate an effect from a nearby disease susceptibility locus. These initial observations are an encouraging step toward the description of non-HLA genetic susceptibility to MS. JAMA. 1997;278:1256-1261

Recent advances in DNA-based human leukocyte antigen (HLA) typing may reveal alternative forms of the genes at the HLA loci, which may aid understanding of HLA matching. HLA is any of the four major genetic markers that are used to determine the level of tissue compatibility between potential bone marrow donors and recipients. Highly compatible tissues decrease the risk that the recipient's immune system will attack the marrow. Standard HLA typing tests cannot distinguish all of the alternative forms of the genes at the HLA class I and class II loci and they have a relatively high error rate. As a result, the biological appearance of HLA in unrelated donors and recipients may be identical, although the DNA is mismatched. Polymerase chain reaction (PCR) tests are a method to copy DNA for analysis. The 'reverse blot' PCR method can identify alternative forms of genes at the HLA class I and class II loci and is suitable for clinical laboratory use.

DNA typing of putative immunity, localized and generalized onchocerciasis in onchocerca volvulus infections reveals that they contain differentially arranged HLA-D alleles in the DQ loci. DQA1*0501-DQBI*0301 haplotype occurs more during putative immunity than in individuals with generalized or localized diseases. The DP allele associates with the localized disease revealing that HLA-D alleles are involved in protective immunity.

Multiple sclerosis (MS) may be caused by genetic changes in components of the immune response system. MS is caused by the destruction of protective tissue, or myelin, in the central nervous system, resulting in weakness, speech disturbances, vision complications and prolonged periods of relapse and remission. A review of MS studies and clinical trials found that MS may be caused by abnormal immune reactions to myelin in individuals with genetic variations. Changes in the major histocompatibility complex, a group of genes on chromosome six, may encode variant proteins that alter the immune response to all antigens including myelin. Similarly, alteration in T-cell receptor genes could change self recognition of antigenic peptides, resulting in incorrect immune responses. Duplication in the myelin protein gene on chromosome 18 has also been associated with MS susceptibility.