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The aim of this study was to explore the role of vitamin D in rheumatoid arthritis (RA) pathogenesis by investigating the enrichment of vitamin D response elements (VDREs) in confirmed RA susceptibility loci and testing variants associated with vitamin D levels for association with RA. Bioinformatically, VDRE genomic positions were overlaid with non-HLA (human leukocyte antigen)-confirmed RA susceptibility regions. The number of VDREs at RA loci was compared to a randomly selected set of genomic loci to calculate an average relative risk (RR). Single-nucleotide polymorphisms (SNPs) in the DHCR7/NADSYN1 (nicotinamide adenine dinucleotide synthase 1) and CYP2R1 loci, previously associated with circulating vitamin D levels, were tested in UK RA cases (n=3870) and controls (n=8430). Significant enrichment of VDREs was seen at RA loci (P=9.23 × 10−8) when regions were defined either by gene (RR 5.50) or position (RR 5.86). SNPs in the DHCR7/NADSYN1 locus showed evidence of positive association with RA, rs4944076 (P=0.008, odds ratio (OR) 1.14, 95% confidence interval (CI) 1.03-1.24). The significant enrichment of VDREs at RA-associated loci and the modest association of variants in loci-controlling levels of circulating vitamin D supports the hypothesis that vitamin D has a role in the development of RA. [ABSTRACT FROM AUTHOR]

Whole-genome association studies in rheumatoid arthritis have identified single-nucleotide polymorphisms (SNPs) predisposing to disease with moderate risk. We aimed to investigate the role of these markers in predicting methotrexate (MTX) response, measured by continuation on MTX monotherapy in patients with recent onset inflammatory polyarthritis (IP). In all, 19 SNPs were genotyped in 736 patients treated with MTX following registration, or not more than 3 months before registration, to the Norfolk Arthritis Register. The association of SNPs with MTX continuation by year 1 and by year 2 was investigated using Cox proportional hazard regression models. A SNP within the OLIG3/TNFAIP3 locus (rs6920220) was associated with being less likely to maintain MTX monotherapy at year 1, hazards ratio (HR) 1.73 (1.18, 2.52) and year 2, HR 1.49 (1.11, 2.00); correlating with an increased in adverse events. Weak evidence for an effect at the PTPN22 locus was also observed. These findings require replication in other large datasets. [ABSTRACT FROM AUTHOR]

The article discusses a study which examined the overlap between genome-wide rare variant rheumatoid arthritis (RA) association signals and the linkage peaks in them. The study included the Wellcome Trust Case Control Consortium (WTCCC) data set. Findings reveal that rare variant association signals are significantly overrepresented under linkage peaks in RA, but the effect is driven by the major histocompatibility complex (MHC).

The aim of this study was to investigate the complex association pattern of the extended major histocompatibility complex (xMHC) region with rheumatoid arthritis (RA) susceptibility to identify effects independent of HLA-DRB1. A total of 1804 RA cases and 1474 controls were included. High-resolution HLA-DRB1 typing was performed. Subjects were genotyped for 1546 single-nucleotide polymorphisms (SNPs) using Affymetrix GeneChip 500 K (Santa Clara, CA, USA) as part of the Wellcome Trust Case Control Consortium Study. Statistical analysis was carried out using PLINK. To avoid confounding by RA-associated HLA-DRB1 alleles, we analyzed xMHC SNPs using a data set with pairwise matching of cases and controls on DRB1 genotypes. A total of 594 case-control pairs with identical DRB1 genotypes were identified. After this adjustment, 104 SNPs remained significantly associated with RA (P<0.05), suggesting that additional RA loci independent of HLA-DRB1 can be found in the xMHC region. Of these, four loci showed the strongest associations with RA (P<0.005): ZNF391, the olfactory receptor (OR) gene cluster, C6orf26-RDBP and HLA-DPB1-COL11A2. An additional locus mapping to the BTN (butyrophilin) cluster showed independent association with RA in anti-cyclic citrullinated peptide-positive patients exclusively. We have validated the previously described independent association of the HLA-DPB1-COL11A2 locus with RA. In addition, association with three novel independent RA loci in the xMHC region (ZNF391, OR2H1 and C6orf26-RDBP) has been detected. [ABSTRACT FROM AUTHOR]

Many autoimmune diseases share common susceptibility loci suggesting similar underlying cellular mechanisms involved in disease expression. The purpose of this investigation was to study 21 genetic variants in 14 genes that are confirmed autoimmune loci in a cohort of patients with early-onset psoriasis. Patients with early-onset psoriasis ( n = 750) and controls ( n = 3531) were genotyped using the Sequenom MassArray™ iPLEX Gold platform. We found strong evidence of association with two variants in the IL2/ IL21 (rs6822844, genotypic P = 3·3 × 10; rs2069778, genotypic P = 7·86 × 10) region. The findings, although requiring replication, suggest that IL2/ IL21 may play a key role in the pathogenesis of psoriasis as well as in other diverse autoimmune diseases. [ABSTRACT FROM AUTHOR]

The CC chemokine receptor 5 (CCR5) has been shown to be important in the recruitment of T-helper cells to the synovium, where they accumulate, drive the inflammatory process and the consequent synovitis and joint destruction. A 32 base-pair insertion/deletion variant (CCR5Δ32) within the gene leads to a frame shift and a nonfunctional receptor. CCR5Δ32 has been investigated for its association with juvenile idiopathic arthritis (JIA), with conflicting results. The aim of this study was to investigate whether CCR5Δ32 is associated with JIA in an UK population. CCR5Δ32 was genotyped in JIA cases (n=1054) and healthy controls (n=3129) and genotype and allele frequencies were compared. A meta-analysis of our study combined with previously published studies was performed. CCR5Δ32 was significantly associated with protection from developing JIA, in this UK data set (Ptrend=0.006, odds ratio (OR) 0.79 95% confidence interval (95% CI): 0.66-0.94). The meta-analysis of all published case-control association studies confirmed the protective association with JIA (P=0.001 OR 0.82 95% CI: 0.73-0.93). CCR5Δ32 is a functional variant determining the number of receptors on the surface of T cells, and it is hypothesized that the level of CCR5 expression could influence the migration of proinflammatory T cells into the synovium and thus susceptibility to JIA. [ABSTRACT FROM AUTHOR]

Recent genetic studies have led to identification of numerous loci that are associated with susceptibility to autoimmune diseases. The strategy of using information from these studies has facilitated the identification of novel juvenile idiopathic arthritis (JIA) susceptibility loci, specifically, PTPN22 and IL2RA. Several novel autoimmune susceptibility loci have recently been identified, and we hypothesise that single-nucleotide polymorphisms (SNPs) within these genes may also be JIA susceptibility loci. Five SNPs within the genes AFF3, IL2/IL21, IL7R, CTLA4 and CD226, previously associated with multiple autoimmune diseases were genotyped, in a large data set of Caucasian JIA patients and controls, and tested for association with JIA. We identified two susceptibility loci for JIA, AFF3 and the IL2/IL21 region and additional weak evidence supporting an association with the CTLA4 and IL7R genes, which warrant further investigation. All results require validation in independent JIA data sets. Further characterisation of the specific causal variants will be required before functional studies can be performed. [ABSTRACT FROM AUTHOR]

Background The use of methotrexate is limited by interindividual variability in response. Previous studies in patients with either rheumatoid arthritis or psoriasis suggest that genetic variation across the methotrexate metabolic pathway might enable prediction of both efficacy and toxicity of the drug. Objectives To assess if single nucleotide polymorphisms (SNPs) across four genes that are relevant to methotrexate metabolism [folypolyglutamate synthase ( FPGS), gamma-glutamyl hydrolase ( GGH), methylenetetrahydrofolate reductase ( MTHFR) and 5-aminoimidazole-4-carboxamide ribonucleotide transformylase ( ATIC)] are related to treatment outcomes in patients with psoriasis. Methods DNA was collected from 374 patients with psoriasis who had been treated with methotrexate. Data were available on individual outcomes to therapy, namely efficacy and toxicity. Haplotype-tagging SNPs ( r2 > 0·8) for the four genes with a minor allele frequency of > 5% were selected from the HAPMAP phase II data. Genotyping was undertaken using the MassARRAY spectrometric method (Sequenom®). Results There were no significant associations detected between clinical outcomes in patients with psoriasis treated with methotrexate and SNPs in the four genes investigated. Conclusions Genetic variation in four key genes relevant to the intracellular metabolism of methotrexate does not appear to predict response to methotrexate therapy in patients with psoriasis. [ABSTRACT FROM AUTHOR]

Background  Psoriasis, a chronic inflammatory skin disease, affects approximately 2% of the population worldwide. Although the aetiology of psoriasis is poorly understood, patients with disease of early onset (Type I, age of onset ≤ 40 years) usually have a strong genetic component to the disease. Objectives  The purpose of this study was to investigate the role of the protein tyrosine phosphatase nonreceptor type 22 ( PTPN22) gene region in susceptibility to Type I psoriasis. Patients and methods  Thirteen single nucleotide polymorphisms (SNPs) mapping to the PTPN22 region were genotyped in 647 patients with Type I psoriasis and 566 normal controls. Results  The rs2476601 (R620W) SNP, widely associated with other inflammatory autoimmune diseases, showed no evidence of association with susceptibility to Type I psoriasis. Two SNPs (rs1217414 and rs3789604) demonstrated significant association with Type I psoriasis and were subsequently genotyped in a further 253 unrelated patients and 2024 normal controls. rs1217414 and rs3789604 were also significantly associated with Type I psoriasis in the combined datasets ( P = 0·003 and P = 0·0002, respectively); furthermore carriage of both risk alleles was also significantly associated ( P = 0·002). Conclusions  This study demonstrates evidence of association of two SNPs (rs1217414 and rs3789604) in the PTPN22 region with Type I psoriasis, providing evidence for a role of this gene in Type I psoriasis that is not conferred by the R620W variant previously associated with a number of inflammatory diseases. [ABSTRACT FROM AUTHOR]

OBJECTIVE: A recent study of rheumatoid arthritis (RA) showed an association with a functional single-nucleotide polymorphism (SNP) mapping to the promoter region of the MHC2TA gene on chromosome 16p13 in a Swedish population. Interestingly, evidence for linkage to this region has been detected previously in a subgroup of UK RA families carrying 2 copies of shared epitope (SE) alleles. Therefore, we undertook this study to investigate the association of the MHC2TA gene promoter with RA in a UK Caucasian population. METHODS: Association with 5 SNPs spanning the promoter region of the MHC2TA gene was investigated in 813 UK RA patients and 532 population controls. Association with a functional putative RA-causal polymorphism (-168*G/A [rs3087456]) was tested in a total of 1,401 UK RA patients and 2,475 controls. Genotyping was performed using a Sequenom MassArray platform. Estimated haplotype frequencies were generated using the expectation-maximization algorithm and compared between patients and controls. RESULTS: All SNPs were in Hardy-Weinberg equilibrium. No evidence for association was found, either with the putative RA-causal polymorphism (-168*G/A) or with the other SNPs tested. Haplotype analysis revealed extensive linkage disequilibrium across the promoter region but no evidence for association. Stratifying the data set by carriage of SE alleles did not alter the conclusions. CONCLUSION: A functional polymorphism of the MHC2TA gene locus previously associated with RA in a European population has not been associated with RA in a UK population. These findings do not provide support for the notion that this gene plays a major role in the etiology of RA. [ABSTRACT FROM AUTHOR]

Background: A functional haplotype of the peptidylarginine deiminase 4 (PADI4) gene has recently been identified as a rheumatoid arthritis susceptibility gene in a Japanese but not in a UK population. One possible explanation for this disparity is that the gene determines severity of rather than susceptibility to inflammatory polyarthritis (IP) and that the UK and Japanese cohorts differed in terms of outcome.Aim: To examine the association between individual PADI4 single nucleotide polymorphisms (SNPs) and haplotypes, with the development and severity of erosions by five years in patients with IP.Methods: 438 patients from the NOAR inception cohort of patients with IP were x rayed five years after presentation with early IP. Association with four exonic SNPs (padi4_89*G/A, padi4_90*T/C, padi4_92*G/C, and padi4_104*T/C), mapping to the PADI4 gene and defining a haplotype previously reported to be associated with rheumatoid arthritis, was investigated. Patients were compared for the presence, extent, and progression of erosions by five years and the presence of antibodies to citrullinated peptide (anti-CCP antibodies).Results: There was no association between individual PADI4 SNPs or haplotypes and the development or extent of erosions by five years. Restricting analysis to patients who satisfied ACR criteria for rheumatoid arthritis by five years did not alter the conclusions. No association with presence of anti-CCP antibodies was detected.Conclusions: No evidence was found for association of the PADI4 gene with severity as assessed by erosive outcome at five years or with presence of anti-CCP antibodies in patients with IP. [ABSTRACT FROM AUTHOR]

The full extent of the polymorphism of ELA-DRA in Equidae is not yet known. Given the apparent differences in DRA polymorphisms between Equidae and other species, the aims of this study were to more fully characterize ELA-DRA, determine the extent of gene polymorphism and establish the allele-frequency distribution. An allele reference panel for the second exon of ELA-DRA was established by sequence-based typing of 69 equine DNA samples consisting of various breeds of domestic horse ( Equus caballus), together with donkeys ( Equus asinus), Grant's zebras ( Equus boehmi) and one onager ( Equus hemionus). Five of the six previously reported alleles detected using single-strand conformation polymorphism were found: ELA-DRA*0101, ELA-DRA*0201, ELA-DRA*0301, ELA-DRA*0501 (Albright-Fraser DG et al. Polymorphism of DRA among equids. Immunogenetics 1996: 43: 315–7) and ELA-DRA*0601 (GenBank accession number ). In addition to the previously reported alleles, five novel ELA-DRA alleles were detected within the ELA-DRA allele reference panel. One of these was identified in E. caballus ( ELA-DRA* ), one in E. boehmi and E. hemionus ( ELA-DRA* ) and three in E. asinus ( ELA-DRA* , ELA-DRA* and ELA-DRA* ). A total of 565 equine DNA samples were screened using reference-strand-mediated conformation analysis, a double-stranded conformation-based mutation detection system that can be used to type existing ELA-DRA alleles and identify new variants. Based on our findings, at least 11 ELA-DRA alleles are now known to exist, and this level of polymorphism at the DRA locus appears to be unique to the genus Equus. Both the previously reported alleles and the new alleles displayed a species-specific distribution. [ABSTRACT FROM AUTHOR]

OBJECTIVE: In the era of postgenomic research, linkage- and association-based strategies are beginning to reveal novel complex disease genes. Using such an approach, a functional haplotype of the peptidylarginine deiminase 4 gene (PADI4) has recently been identified as a gene conferring susceptibility to rheumatoid arthritis (RA) in a Japanese population. In the present study, we investigated the association of single-nucleotide polymorphisms (SNPs) in the PADI4 gene with RA in a UK population. METHODS: Association with 4 exonic SNPs (padi4_89*G/A, padi4_90*T/C, padi4_92*G/C, and padi4_104*T/C), mapping to the PADI4 gene and defining a haplotype previously reported to be associated with RA, was investigated. Genotyping was performed using 5' allelic discrimination assays. Estimated haplotypes were generated using the expectation-maximization algorithm, and frequencies of the SNPs and haplotypes were compared between unrelated Caucasian RA patients from the UK (n = 839) and population controls (n = 481). RESULTS: Allele frequencies for the 4 SNPs in the UK population were similar to those reported in the Japanese control population, but none of these was associated with RA. As in the Japanese population, the SNPs in the UK population defined 2 major haplotypes, but neither was associated with RA (P = 0.79). CONCLUSION: A PADI4 susceptibility haplotype associated with RA in a Japanese population is not associated with RA in a UK population. Other genes involved in the citrullinating pathway remain strong candidate RA-susceptibility genes and require further investigation. [ABSTRACT FROM AUTHOR]

Background: Tumour necrosis factor alpha (TNFalpha) is a powerful inflammatory mediator in rheumatoid and other types of inflammatory arthritis. Polymorphisms within the TNFalpha gene have previously been investigated to determine their role in the aetiopathogenesis of rheumatoid arthritis (RA), but it is unclear whether reported associations are with susceptibility to, or severity of, disease.Objective: To examine the association between both individual TNFalpha single nucleotide polymorphisms (SNPs) and haplotypes with the development and severity of erosions by 5 years in patients with inflammatory polyarthritis (IP).Methods: 438 patients from the Norfolk Arthritis Register observational inception cohort of patients with IP were x rayed 5 years after disease onset. They were genotyped for nine SNPs mapping to the TNFalpha gene, using a SNaPshot primer extension assay. Haplotypes were constructed in patients with IP, who were compared for the presence and extent of erosions at 5 years.Results: No association between individual TNFalpha SNPs or haplotypes in the patients who developed erosions at 5 years compared with those who remained non-erosive was found. Restricting analysis to patients who satisfied ACR criteria for RA by 5 years did not affect the conclusions.Conclusion: The TNFalpha gene does not seem to be associated with severity as assessed by erosive outcome at 5 years in patients with IP. [ABSTRACT FROM AUTHOR]

We have investigated a family with an autosomal dominant form of spondyloepiphyseal dysplasia (SED) characterised by short stature and severe premature degenerative arthropathy. Previous studies have excluded linkage between this condition and the locus for the type II collagen gene. Here we report the identification of linkage between this disorder and a locus on the long arm of chromosome 15 between markers D15S979 and D15S1004. According to current linkage maps and sequence data, this locus includes that of the aggrecan gene (AGC1). Our linkage data from the SED family show, however, that AGC1 maps to a locus that is proximal to D15S979. This proximal location for AGC1 is further supported by linkage data from a second family with an autosomal recessive form of multiple epiphyseal dysplasia that also maps to the SED locus. In both families AGC1 is therefore excluded as a candidate gene. [ABSTRACT FROM AUTHOR]

Rheumatoid arthritis (RA) is an oligogenic autoimmune disease but, to date, linkage and association to major histocompatibility complex (MHC) has been the only consistent finding in genetic studies. However, MHC is estimated to contribute only 30–40% of the total genetic component to disease susceptibility. Studies in animal models of inflammatory arthritis have identified a number of putative vulnerability loci but the homologous regions in the human genome have not previously been investigated as candidate RA susceptibility loci. We have investigated linkage to five regions homologous to those identified in animal models of inflammatory arthritis in RA affected sibling pair (ASP) families. Linkage to 17q22 syntenic to a susceptibility locus common to two experimental rat models was detected in 200 RA ASP families and replicated in a further 100 RA ASP families. Linkage to additional markers mapping to the area has refined the extent of linkage to a 4 cM region. Association to one of the markers (D17S807) was demonstrated in this cohort using extensions of the transmission disequilibrium test. Association to two 2-marker haplotypes including this marker was detected in an independent cohort of single-case RA families, thus narrowing the region harbouring the aetiological mutation to ∼1 cM. This is the first time that an arthritis susceptibility locus mapped in experimental animal models of disease has been used to identify a novel RA susceptibility locus in humans. The difficult task of identifying a disease mutation from a linkage result should, in this case at least, be facilitated by the combined use of animal and human based investigations. [ABSTRACT FROM AUTHOR]

Biological scientists are eagerly confronting the challenge of understanding the regulatory mechanisms that control the cell division cycle in eukaryotes. New information will have major implications for the treatment of growth-related diseases and cancer in animals. In plants, cell division has a key role in root and shoot growth as well as in the development of vegetative storage organs and reproductive tissues such as flowers and seeds. Many of the strategies for crop improvement, especially those aimed at increasing yield, involve the manipulation of cell division. This review describes, in some detail, the current status of our understanding of the regulation of cell division in eukaryotes and especially in plants. It also features an outline of some preliminary attempts to exploit transgenesis for manipulation of plant cell division. [ABSTRACT FROM AUTHOR]

An abstract of the conference paper "Replication of the association of the COG6 gene with juvenile idiopathic arthritis (JIA)," by Femke Van Wijk and colleagues is presented.

We have identified two novel polymorphisms in the transforming growth factor beta 2 (TGFβ2) gene; an insertion in the 5-′ untranslated region (5′ UTR) and a single nucleotide polymorphism (SNP) in exon 1. A 895-bp fragment was analysed covering part of the 5′UTR and exon 1. Single-strand conformation polymorphism (SSCP) analysis of polymerase chain reaction (PCR) products was performed to detect sequence variations. This was followed by the sequencing of samples demonstrating distinct banding patterns. A 4-bp insertion (ACAA) in the 5′ UTR and a SNP (G > A) within exon 1 was identified. The 5′UTR polymorphism was found to be common in three Caucasian populations from Spain, Turkey and the UK. Exon I polymorphism is rare and results in an R to H amino acid substitution in codon 91. Both polymorphisms may prove useful for investigating possible associations of TGFβ2 with disease. Genes and Immunity (2001) 2, 295-296. [ABSTRACT FROM AUTHOR]