OBJECTIVE:apply Juvenile idiopathic arthritis (JIA) is a chronic rheumatic disease of childhood. Two well-established genetic factors known to contribute to JIA 1,847 susceptibility, HLA and PTPN22, account for less than half of the genetic susceptibility to disease; therefore, additional genetic factors have 112 yet to be identified. The purpose of this study was to perform a systematic search of the genome to identify additional novel susceptibility loci for JIA. METHODS: A genome-wide association study using Affymetrix GeneChip 100K arrays was performed in a discovery additional cohort (279 cases and 184 controls). Single-nucleotide polymorphisms (SNPs) showing the most significant differences between cases and controls were then discovery genotyped in a validation sample of cases (n = 321) and controls, combined with control data from the 1958 UK novel birth cohort (n = 2,024). In one region in which association was confirmed, fine-mapping was performed (654 cases and 1,847 OBJECTIVE: controls). RESULTS: Of the 112 SNPs that were significantly associated with JIA in the discovery cohort, 6 SNPs were associated to with JIA in the independent validation cohort. The most strongly associated SNP mapped to the HLA region, while the second defined strongest association was with a SNP within the VTCN1 gene. Fine-mapping of that gene was performed, and 10 SNPs were SNPs found to be associated with JIA. CONCLUSION: This study is the first to successfully apply a SNP-based genome-wide association approach cases to the investigation of JIA. The replicated association with markers in the VTCN1 gene defined an additional susceptibility locus for the JIA and implicates a novel pathway in the pathogenesis of this chronic disease of childhood.

AIM:polymorphism We examined genetic polymorphisms in the renin-angiotensin system (RAS) coding for angiotensin I-converting enzyme (ACE) insertion/deletion (I/D) for angiotensinogen (AGT)genotypes M235T and angiotensin II receptor type 1 (AGTR1) A1166C as predictors for the development of microalbuminuria (MA) in children with ACE-II type 1 diabetes mellitus (T1DM). METHODS: Four hundred fifty-three (215 males, 238 females) T1DM children [median (interquartile range): age, 16.7 that years (13.9-18.3); diabetes duration, 6.9 years (3.3-10.8); age at diagnosis, 9.1 years (5.8-11.8)] were followed prospectively from diagnosis until the of development of MA (two of three consecutive overnight urine samples with albumin excretion rates of >/=20 and <200 mug/min). Kaplan-Meier (n=450); survival curves and Cox proportional multivariate model estimated the probability of developing MA and the relative risk for MA among range): different variables. RESULTS: MA developed in 41 (9.1%) subjects. The frequencies of genotypes were as follows: ACE-II 112 (25%), ACE-ID AIM: 221 (49%), and ACE-DD 117 (26%)(n=450); AGT-MM 144 (32%), AGT-MT 231 (51%), and AGT-TT 77 (17%)(n=452); AGTR1-AA 211 for (47%), AGTR1-AC 204 (45%), and AGTR1-CC 37 (8%)(n=452). The cumulative risk for the development of MA was higher in findings ACE-DD versus ACE-ID/II groups (log-rank test, P=.05), and a trend was noticed when AGT-TT was compared to AGT-MT/MM groups (log-rank (32%), test, P=.08). AGT-TT polymorphism conferred a fourfold increased risk for MA compared to AGT-MM/MT (hazard ratio=3.8; 95% confidence interval=1.43-10.3; P=.008).until INTERPRETATION: Our findings suggest that RAS gene polymorphism at AGT M235T is a strong predictor for early MA in young consecutive T1DM subjects.

Despite for the theoretical evidence of the utility of single-nucleotide polymorphisms (SNPs) for linkage analysis, no whole-genome scans of a complex disease than have yet been published to directly compare SNPs with microsatellites. Here, we describe a whole-genome screen of 157 families with number multiple cases of rheumatoid arthritis (RA), performed using 11,245 genomewide SNPs. The results were compared with those from a 10-cM be microsatellite scan in the same cohort. The SNP analysis detected HLA*DRB1, the major RA susceptibility locus (P=.00004), with a linkage families interval of 31 cM, compared with a 50-cM linkage interval detected by the microsatellite scan. In addition, four loci were caused detected at a nominal significance level (P<.05) in the SNP linkage analysis; these were not observed in the microsatellite scan.the We demonstrate that variation in information content was the main factor contributing to observed differences in the two scans, with Despite the SNPs providing significantly higher information content than the microsatellites. Reducing the number of SNPs in the marker set to disease 3,300 (1-cM spacing) caused several loci to drop below nominal significance levels, suggesting that decreases in information content can have loci significant effects on linkage results. In contrast, differences in maps employed in the analysis, the low detectable rate of genotyping loci error, and the presence of moderate linkage disequilibrium between markers did not significantly affect the results. We have demonstrated the a utility of a dense SNP map for performing linkage analysis in a late-age-at-onset disease, where DNA from parents is not In always available. The high SNP density allows loci to be defined more precisely and provides a partial scaffold for association SNPs studies, substantially reducing the resource requirement for gene-mapping studies.

OBJECTIVE:siblings A previous whole-genome scan (WGS) of 182 UK rheumatoid arthritis (RA) affected sibling pair (ASP) families suggested linkage to HLA in and 11 other chromosome regions. Replication of such findings in an independent cohort can help to distinguish true linkages from achieved false-positive linkages. Since RA is a heterogeneous disease, some loci may be linked only in subsets of patients. Thus, the information aim of this study was to investigate in an additional set of RA ASP families linkage to regions showing deviation true in expected allele-sharing ratios in the UK WGS and to perform subset analysis on the combined cohort. METHODS: Twenty loci analysis, were investigated for linkage in 217 Caucasian UK RA ASPs. Stratification analysis was performed on the combined cohort of 377 of RA ASP families to account for sex, RA severity, and the shared epitope (SE). RESULTS: None of the regions of OBJECTIVE: linkage identified in the initial WGS achieved statistical significance in the second cohort. In contrast, after stratification analysis, 14 regions to showed nominal evidence of linkage (logarithm of odds score > .8) in one or more subgroups. In particular, the strength of RA. evidence for linkage to chromosome 16p was increased in subsets of ASPs with younger age at disease onset (LOD score showed 2.38) and for linkage to chromosome 6q in female-female ASPs (LOD score 2.31) and in ASPs in which both siblings in had 2 copies of the SE (LOD score 3.03). CONCLUSION: These results support the evidence for heterogeneity of RA. This analysis information will inform the future design of association-based investigations as the search for disease genes in the linked regions begins.the

ABSTRACT antibodies, : The aim of this study was to investigate HLA class II associations in polymyositis (PM) and dermatomyositis (DM), and anti-Mi-2 to determine how these associations influence clinical and serological differences. DNA samples were obtained from 225 UK Caucasian idiopathic inflammatory PM myopathy patients (PM = 117, DM = 108) and compared with 537 randomly selected UK Caucasian controls. All cases had patients also been assessed for the presence of related malignancy and interstitial lung disease (ILD), and a number of myositis-specific/myositis-associated antibodies from (MSAs/MAAs). Subjects were genotyped for HLA-DRB1, DQA1 and DQB1. HLA-DRB1*03, DQA1*05 and DQB1*02 were associated with an increased risk for even both PM and DM. The HLA-DRB1*03-DQA1*05-DQB1*02 haplotype demonstrated strong association with ILD, irrespective of myositis subtype or presence of anti-aminoacyl-transfer controls. RNA synthetase antibodies. The HLA-DRB1*07-DQA1*02-DQB1*02 haplotype was associated with risk for anti-Mi-2 antibodies, and discriminated PM from DM (odds ratio ABSTRACT .3, 95% confidence interval .1- .6), even in anti-Mi-2 negative patients. Other MSA/MAAs showed specific associations with other HLA class II dermatomyositis haplotypes, irrespective of myositis subtype. There were no genotype, haplotype or serological associations with malignancy. The HLA-DRB1*03-DQA1*05-DQB1*02 haplotype associations appear that to not only govern disease susceptibility in Caucasian PM/DM patients, but also phenotypic features common to PM/DM. Though strongly associated anti-Mi-2 with anti-Mi-2 antibodies, the HLA-DRB1*07-DQA1*02-DQB1*02 haplotype shows differential associations with PM/DM disease susceptibility. In conclusion, these findings support the notion of that myositis patients with differing myositis serology have different immunogenetic profiles, and that these profiles may define specific myositis subtypes.HLA-DRB1,

OBJECTIVE:or In vitro and animal studies have implicated osteopontin (OPN) in the pathogenesis of aortic aneurysm. The relationship between serum concentration with of OPN and variants of the OPN gene with human abdominal aortic aneurysm (AAA) was investigated. METHODS AND RESULTS: OPN aortic genotypes were examined in 4227 subjects in which aortic diameter and clinical risk factors were measured. Serum OPN was measured variation by ELISA in two cohorts of 665 subjects. The concentration of serum OPN was independently associated with the presence of (AAA) AAA. Odds ratios (and 95% confidence intervals) for upper compared with lower OPN tertiles in predicting presence of AAA were growth 2.23 (1.29 to 3.85, P= .004) for the population cohort and 4.08 (1.67 to 10.00, P= .002) for the referral cohort after measured. adjusting for other risk factors. In 198 patients with complete follow-up of aortic diameter at 3 years, initial serum OPN OBJECTIVE: predicted AAA growth after adjustment for other risk factors (standardized coefficient .24, P= .001). The concentration of OPN in the aortic relationship wall was greater in patients with small AAAs (30 to 50 mm) than those with aortic occlusive disease alone. There between was no association between five single nucleotide polymorphisms or haplotypes of the OPN gene and aortic diameter or AAA expansion.adjustment CONCLUSIONS: Serum and tissue concentrations of OPN are associated with human AAA. We found no relationship between variation of the associated OPN gene and AAA. OPN may be a useful biomarker for AAA presence and growth.

OBJECTIVE:and HLA is the most strongly associated locus in rheumatoid arthritis (RA), accounting for up to one-third of the genetic contribution.identify Conditioning on the effect of true disease loci such as HLA can lead to increased power to detect effects at 2-locus other loci and, in addition, allows investigation of the underlying disease models, including interactions. The aim of this study was harbor to detect susceptibility loci for RA by conditioning on HLA in a large sample of affected sibling pairs (ASPs) and detect to test for evidence of interaction between novel loci and HLA. METHODS: Genotype data from 3 whole-genome linkage scans for loci RA in a US population and a UK population were pooled, resulting in a combined data set of 886 ASPs.detect This pooling of data increased the power to detect loci showing low levels of heterogeneity. Nonparametric linkage analysis was performed OBJECTIVE: to identify regions of interest. Joint 2-locus analysis was then performed for HLA and each of the loci that demonstrated genetic evidence of linkage in the 886 ASPs. RESULTS: Evidence for linkage was most significant at HLA (P = 4 x 16p 10(-16)), with 7 non-HLA loci showing some evidence for linkage (P = .05- .003). Joint modeling of these loci with HLA demonstrated provided evidence for linkage at a genome-wide significance level for loci on 6q (P = 2.7 x 10(-6)) and 16p evidence (P = 2 x 10(-4)). CONCLUSION: These data provide the most convincing evidence to date that 6q and 16p harbor Genotype susceptibility genes. In addition, these loci may interact with HLA, facilitating the search for candidate genes within this region.

ABSTRACT the : A common dilemma arising in linkage studies of complex genetic diseases is the selection of positive signals, their follow-up that with association studies and discrimination between true and false positive results. Several strategies for overcoming these issues have been devised.did Using the Genetic Analysis Workshop 14 simulated dataset, we aimed to apply different analytical approaches and evaluate their performance in well-powered discerning real associations. We considered a) haplotype analyses, b) different methods adjusting for multiple testing, c) replication in a second between dataset, and d) exhaustive genotyping of all markers in a sufficiently powered, large sample group. We found that haplotype-based analyses although did not substantially improve over single-point analysis, although this may reflect the low levels of linkage disequilibrium simulated in the the datasets provided. Multiple testing correction methods were in general found to be over-conservative. Replication of nominally positive results in a ABSTRACT second dataset appears to be less stringent, resulting in the follow-up of false positives. Performing a comprehensive assay of all is markers in a large, well-powered dataset appears to be the most effective strategy for complex disease gene identification.

Microabstract for Using a moderate-sized cohort selected with extreme BMD (n=344, absolute value BMD 1.5-4. ), significant association of several members of the bone Wnt signalling pathway with bone densitometry measures was demonstrated. This confirms that extreme-truncate selection is a powerful design for quantitative densitometry trait association studies of bone phenotypes.

AIM:polymorphism We examined genetic polymorphisms in the renin-angiotensin system (RAS) coding for angiotensin I-converting enzyme (ACE) insertion/deletion (I/D) for angiotensinogen (AGT)genotypes M235T and angiotensin II receptor type 1 (AGTR1) A1166C as predictors for the development of microalbuminuria (MA) in children with ACE-II type 1 diabetes mellitus (T1DM). METHODS: Four hundred fifty-three (215 males, 238 females) T1DM children [median (interquartile range): age, 16.7 that years (13.9-18.3); diabetes duration, 6.9 years (3.3-10.8); age at diagnosis, 9.1 years (5.8-11.8)] were followed prospectively from diagnosis until the of development of MA (two of three consecutive overnight urine samples with albumin excretion rates of >/=20 and <200 mug/min). Kaplan-Meier (n=450); survival curves and Cox proportional multivariate model estimated the probability of developing MA and the relative risk for MA among range): different variables. RESULTS: MA developed in 41 (9.1%) subjects. The frequencies of genotypes were as follows: ACE-II 112 (25%), ACE-ID AIM: 221 (49%), and ACE-DD 117 (26%)(n=450); AGT-MM 144 (32%), AGT-MT 231 (51%), and AGT-TT 77 (17%)(n=452); AGTR1-AA 211 for (47%), AGTR1-AC 204 (45%), and AGTR1-CC 37 (8%)(n=452). The cumulative risk for the development of MA was higher in findings ACE-DD versus ACE-ID/II groups (log-rank test, P=.05), and a trend was noticed when AGT-TT was compared to AGT-MT/MM groups (log-rank (32%), test, P=.08). AGT-TT polymorphism conferred a fourfold increased risk for MA compared to AGT-MM/MT (hazard ratio=3.8; 95% confidence interval=1.43-10.3; P=.008).until INTERPRETATION: Our findings suggest that RAS gene polymorphism at AGT M235T is a strong predictor for early MA in young consecutive T1DM subjects.

BACKGROUND:analyses. The design of appropriate strategies to analyze and interpret linkage results for complex human diseases constitutes a challenge. Parameters such performed as power, definition of phenotype, and replicability have to be taken into account in order to reach meaningful conclusions. Incorporating significance data on repeated phenotypic measures may increase the power to detect linkage but requires sophisticated analysis methods. Using the simulated dismissed; Genetic Analysis Workshop 13 data set, we have estimated a variety of systolic blood pressure (SBP) phenotypic measures and examined to their performance with respect to consistency among replicates and to true and false positive linkage signals. RESULTS: The whole-genome scan from conducted on a dichotomous hypertension phenotype indicated the involvement of few true loci with nominal significance and gave rise to Using a high rate of false positives. Analysis of a cross-sectional quantitative SBP measure performed better, although genome-wide significance was again BACKGROUND: not reached. Additional phenotypic measures were derived from the longitudinal data using random effects modelling for censored data with varying challenge. levels of covariate adjustment. These models provided evidence for significant linkage to most genes influencing SBP and produced few false not positive results. Overall, replicability of results was poor for loci, representing weak effects. CONCLUSION: Longitudinally derived phenotypes performed better than longitudinal cross-sectional measures in linkage analyses. Bearing in mind the sample design and size of these data, linkage results that fail and to replicate should not be dismissed; instead, different lines of evidence derived from complementary analysis methods should be combined to among prioritize follow up.

ABSTRACT:putative The IDDM8 region on chromosome 6q27, first identified as a susceptibility locus for type 1 diabetes, has previously been linked 50 and associated with rheumatoid arthritis. The region contains a number of potential candidate genes including programmed cell death 2 (PDCD2),association the proteosome subunit beta type 1 (PSMB1), delta-like ligand 1 (DLL-1) and TATA box-binding protein (TBP) amongst others. The aim failed of this study was to fine map the IDDM8 region on chromosome 6q27, focusing on the genes in the region,programmed to identify polymorphisms that may contribute to susceptibility to RA and potentially to other autoimmune diseases Validated single nucleotide polymorphisms a (SNPs)(n=65) were selected from public databases from the 330kb region of IDDM8. These were genotyped using Sequenom MassArray genotyping The technology in two datasets; the test dataset comprised 180 RA cases and 180 controls. 50 SNPs were tested for association ABSTRACT: with RA and any significant associations were genotyped in a second dataset of 174 RA cases and 192 controls, and previously the datasets were combined before analysis. Association analysis was performed by chi-square test implemented in Stata software and linkage disequilibrium has and haplotype analysis was performed using Helix tree version 4.1. There was initial weak evidence of association, with RA, of dataset a number of SNPs around the loc154449 putative gene and within the KIAA1838 gene however these associations were not significant region, in the combined dataset. Our study has failed to detect evidence of association with any of the known genes mapping susceptibility to the IDDM8 locus with RA.