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Objective Several copy number variations (CNVs) have been found to be associated with systemic lupus erythematosus (SLE) through the target gene approach. However, genome-wide features of CNVs and their role in the risk of SLE remain unknown. The aim of this study was to identify SLE-associated CNVs in Korean women. Methods Genome-wide assessments of CNVs were performed in 382 SLE patients and 191 control subjects, using an Illumina HumanHap610 BeadChip genotyping platform. SLE-associated CNV regions that were identified by genome-wide association study (GWAS) were replicated in quantitative polymerase chain reaction (PCR) and deletion-typing PCR analyses in an independent sample set comprising 564 SLE patients and 511 control subjects. Results Of 144 common CNV regions, 3 deletion-type CNV regions in 1q25.1, 8q23.3, and 10q21.3 were found to be significantly associated with SLE by GWAS analysis. In the independent replication, the CNV regions in 1q25.1 ( RABGAP1L) and 10q21.3 were successfully replicated (odds ratio [OR] 1.30, P = 0.038 and OR 1.90, P = 3.6 × 10−5, respectively), and the associations were confirmed again by deletion-typing PCR. The CNV region in the C4 gene, which showed a potential association in the discovery stage, was included in the replication analysis and was found to be significantly associated with the risk of SLE (OR 1.88, P = 0.01). Through deletion-typing PCR, the exact sizes and breakpoint sequences of the deletions were defined. Individuals with the deletions in all 3 loci ( RABGAP1L, 10q21.3, and C4) had a much higher risk of SLE than did those without any deletions in the 3 loci (OR 5.52, P = 3.9 × 10−4). Conclusion These CNV regions can be useful to identify the pathogenic mechanisms of SLE, and might be used to more accurately predict the risk of SLE by taking into consideration their synergistic effects on disease susceptibility. [ABSTRACT FROM AUTHOR]

Objective. To investigate the health-related quality of life (HRQOL) and economic burden of patients with FM syndrome (FMS) and compare the changes in these parameters 3 months before and after FMS diagnosis.Methods. A total of 2098 patients with FMS (1818 previously diagnosed with FMS and 280 newly diagnosed with FMS) were enrolled in this study. The newly diagnosed patients with FMS participated in a 3-month prospective observational study to assess HRQOL and economic burden in terms of direct health-care costs, direct non-health-care costs and indirect costs. HRQOL was estimated using the Short Form 36 Health Survey.Results. Mean (s.d.) scores obtained on the physical component summary (PCS) and mental component summary (MCS) scales by patients with FMS were 34.01 (7.28) and 37.29 (11.17), respectively. The total expenditure for the 3 months before enrolment was $1481 (s.d. $2206). Indirect costs [$1126 (s.d. $2016)] were about three times higher than direct costs [$355 (s.d. $534)]. The PCS and MCS scores increased to 4.03 (s.d. 6.79) and 4.06 (s.d. 10.57), respectively, 3 months after the initial FMS diagnosis (P < 0.001, both). Total expenditure after FMS diagnosis was reduced by $1025 (s.d. $1347) as compared with costs before FMS diagnosis (P < 0.001).Conclusion. Patients with FMS experience a decline in their HRQOL and constitute a significant economic burden on health-service utilization. The improvement in health-related costs and HRQOL after a diagnosis of FMS demonstrates a need for early diagnosis and treatment of FMS to reduce costs and enhance HRQOL. [ABSTRACT FROM AUTHOR]

PXK was identified as a novel candidate gene for systemic lupus erythematosus (SLE) from genome-wide association studies (GWAS) in Caucasians. But a recent replication study in Hong Kong Chinese reported that PXK was not associated with SLE. The aim of this study was to determine whether PXK is associated with SLE in Koreans. We genotyped single nucleotide polymorphism (SNP) rs6445975 of PXK using the TaqMan assay in 527 Korean patients with SLE and 517 healthy Korean control subjects. Genotypic associations were assessed using multiple logistic regression models. Additional analyses were also performed by subphenotype stratification. No association was detected between PXK rs6445975 and SLE (odds ratio (OR) = 1.06, P = 0.57). PXK rs6445975 showed positive associations with photosensitivity ( P = 0.02) and the production of anti-Sm Ab ( P = 0.04) among SLE patients. Thus, the association of PXK rs6445975 with SLE that was previously observed in Caucasians was not replicated in Koreans or in Hong Kong Chinese. It is possible that PXK has different genetic contribution on SLE between Caucasians and Asians and that the gene is associated with disease subphenotypes rather than with overall susceptibility. [ABSTRACT FROM AUTHOR]

In an effort to discover non-HLA genes affecting susceptibility to type 1 diabetes (T1D), we have investigated the association of polymorphisms in STAT4, an important signaling molecule of IL-12, γIFN, and IL-23, in a sample of 389 T1D patients and 152 nondiabetic controls in Korea. Four SNPs on chromosome 2q, which were recently found to be associated with rheumatoid arthritis, were examined for association and linkage disequilibrium. We found that neither alleles or genotypes among all four SNPs nor reconstructed haplotypes of the three SNPs within the same LD block (rs7574865, rs8179673, and rs10181656) were associated with susceptibility to T1D. When we stratified T1D patients into early-onset and late-onset subgroups on the basis of fewer or more than 7.8 years of age at diagnosis, however, the minor alleles of three SNPs (rs7574865, rs8179673, and rs10181656) showed a significant association with susceptibility to T1D in the early-onset subgroup (i.e., rs7574865, OR = 1.44 [1.03–2.01], P < 0.05), but not in the late-onset subgroup, suggesting that STAT4 is related to earlier development of T1D. The analysis of genotypes and haplotypes of the same SNPs (rs7574865, rs8179673, and rs10181656) showed very comparable degrees of risk for T1D. The age at diagnosis is lowest in the patients carrying the homozygotes of a minor allele, middle in the heterozygotes, and highest in the homozygotes of a major allele, suggesting the dosage effects of risk alleles on the age of onset of disease. Recognizing that only the early-onset cases might represent the true autoimmune T1D in Asian populations, we see that STAT4 alleles and haplotype might influence cytokine signaling and, therefore, development of T1D. [ABSTRACT FROM AUTHOR]

Abstract: Objective: Numerous epidemiologic data have shown that smoking may play a role in the disease manifestations or severity of chronic musculoskeletal pain. The authors of the present study investigated the effect of smoking on clinical features such as pain, fatigue, functional impairment, and psychiatric features in the Korean population with fibromyalgia syndrome (FMS). Methods: A total of 336 patients with FMS were consecutively enrolled from 10 medical centers which participated in the Korean national fibromyalgia survey. Smoking was divided into current smokers and non-smokers. Instruments of FMS assessment included tender points, Fibromyalgia Impact questionnaire (FIQ), 36-item Medical Outcomes Study Short-Form Health Survey (SF-36), Brief Fatigue Inventory (BFI), Brief Depression Inventory (BDI), State-Trait Anxiety Inventory (STAI)-1 and STAI-2, and social family support and social friend support. Statistical analyses included Chi-square test, Fisher''s exact test, Mann-Whitney U test, and multivariate logistic regression analysis. Results: Thirty-three patients (9.8%) out of 336 participants were current smokers. The number of tender points (P =0.037), BFI (P =0.026), general health of SF-36 (P =0.028), BDI (P =0.014), syncope (P =0.024), and reflex sympathetic dystrophy (P =0.003) showing significance between current smokers and non-smokers were not associated with smoking habits after adjustment. The significance of the number of tender points (P =0.009), scores of total tender points (P =0.032), BDI (P =0.038), general weakness (P =0.047), and reflex sympathetic dystrophy (P =0.011) was observed between randomized non-smokers (n =55) and smokers (n =33). In addition, the number of tender points (P =0.027, OR=1.379) was associated with smoking status after adjustment. The analysis between randomized non-smokers (n =45) and smokers (n =22) in female FMS patients showed that BDI in FMS was associated with smoking status (P =0.023, OR=1.077) after logistic regression analysis. Conclusions: This study revealed that smoking habits may, in part, influence pain or functional and psychiatric features in FMS patients. The impact of smoking on clinical features in FMS should be assessed in a larger study population. [Copyright &y& Elsevier]

Objective: To perform a genome-wide association study (GWAS) in Koreans in order to identify susceptibility loci for rheumatoid arthritis (RA)., Methods: We generated high-quality genotypes for 441,398 single-nucleotide polymorphisms (SNPs) in 801 RA cases and 757 controls. We then tested 79 markers from 46 loci for replication in an independent sample of 718 RA cases and 719 controls., Results: Genome-wide significance (P < 5 × 10(-08) ) was attained by markers from the major histocompatibility complex region and from the PADI4 gene. The replication data showed nominal association signals (P < 5 × 10(-02) ) for markers from 11 of the 46 replicated loci, greatly exceeding random expectation. Genes that were most significant in the replication stage and in the combined analysis include the known European RA loci BLK, AFF3, and CCL21. Thus, in addition to the previously associated STAT4 alleles, variants at these three loci may contribute to RA not only among Europeans, but also among Asians. In addition, we observed replication signals near the genes PTPN2, FLI1, ARHGEF3, LCP2, GPR137B, TRHDE, and CGA1. Based on the excess of small P values in the replication stage study, we estimate that more than half of these loci are genuine RA susceptibility genes. Finally, we systematically analyzed the presence of association signals in Koreans at established European RA loci, which showed a significant enrichment of European RA loci among the Korean RA loci., Conclusion: Genetic risk for RA involves both population-specific loci as well as many shared genetic susceptibility loci in comparisons of Asian and European populations., (Copyright © 2011 by the American College of Rheumatology.)

Objective: Recent studies have identified a number of novel rheumatoid arthritis (RA) susceptibility loci in Caucasian populations. The aim of this study was to determine whether the genetic variants at 4q27, 6q23, CCL21, TRAF1/C5, and CD40 identified in Caucasians are also associated with RA in a Korean case-control collection. We also comprehensively evaluated the genetic variation within PTPN22, a well-established autoimmune disease-associated gene., Methods: We designed an experiment to thoroughly evaluate the PTPN22 linkage disequilibrium region, using tag single-nucleotide polymorphisms (SNPs) and disease-associated SNPs at 5 RA-associated loci recently identified in Caucasians, in 1,128 Korean patients with RA and 1,022 ethnically matched control subjects. We also resequenced the PTPN22 gene to seek novel coding variants that might be contributing to disease in this population., Results: None of the susceptibility loci identified in Caucasian patients with RA contributed significantly to disease in Koreans. Although tag SNPs covering the PTPN22 linkage disequilibrium block were polymorphic, they did not reveal any disease association, and resequencing did not identify any new common coding region variants in this population. The 6q23 and 4q27 SNPs assayed were nonpolymorphic in this population, and the TRAF1/C5, CD40, and CCL21 SNPs did not show any evidence for association with RA in this population of Korean patients., Conclusion: The genetic risk factors for RA are different in Caucasian and Korean patients. Although patients of different ethnic groups share the HLA region as a major genetic risk locus, most other genes shown to be significantly associated with disease in Caucasians appear not to play a role in Korean patients with RA.

A recent study in the North American White population has documented the association of a common STAT4 haplotype (tagged by rs7574865) with risk for rheumatoid arthritis (RA) and systemic lupus erythematosus. To replicate this finding in the Korean population, we performed a case-control association study. We genotyped 67 single nucleotide polymorphisms (SNPs) within the STAT1 and STAT4 regions in 1123 Korean patients with RA and 1008 ethnicity-matched controls. The most significant four risk SNPs (rs11889341, rs7574865, rs8179673, and rs10181656 located within the third intron of STAT4) among 67 SNPs are identical with those in the North American study. All four SNPs have modest risk for RA susceptibility (odds ratio 1.21-1.27). A common haplotype defined by these markers (TTCG) carries significant risk for RA in Koreans [34 percent versus 28 percent, P=0.0027, OR (95 percent CI)=1.33 (1.10-1.60)]. By logistic regression analysis, this haplotype is an independent risk factor in addition to the classical shared epitope alleles at the HLA-DRB1 locus. There were no significant associations with age of disease onset, radiographic progression, or serologic status using either allelic or haplotypic analysis. Unlike several other risk genes for RA such as PTPN22, PADI4, and FCRL3, a haplotype of the STAT4 gene shows consistent association with RA susceptibility across Whites and Asians, suggesting that this risk haplotype predates the divergence of the major racial groups.

Objective: Anticitrullinating autoantibodies are specific markers for rheumatoid arthritis (RA). A functional haplotype of 4 exonic single-nucleotide polymorphisms (SNPs) in a citrullinating enzyme, peptidylarginine deiminase 4 (PADI4), was shown to be associated with susceptibility to RA in a Japanese population and was shown to increase the stability of PADI4 messenger RNA. However, the association was not confirmed in 4 subsequent studies involving Caucasian RA patients living in the UK, a French Caucasian population, and a Spanish population. The aim of the current study was to investigate the association of SNPs in the PADI4 gene with RA in a Korean population., Methods: Four exonic SNPs of the PADI4 gene (padi4&#95;89, padi4&#95;90, padi4&#95;92, and padi4&#95;104) were genotyped in 545 unrelated patients with RA and 392 controls, using the MassArray SNP genotyping system. Allelic, genotypic, and haplotypic associations of the SNPs with RA susceptibility were examined using the chi-square test and multivariate logistic regression analyses., Results: Increased RA susceptibility was significantly associated with the minor alleles of padi4&#95;89 (P = 2.3 x 10(-5)), padi4&#95;90 (P = 2.3 x 10(-5)), padi4&#95;92 (P = 2.1 x 10(-5)), and padi4&#95;104 (P = 1.1 x 10(-3)) and the haplotype carrying the 4 minor alleles (P = 1.0 x 10(-4)). Genotypes carrying the minor alleles and HLA-DRB1 shared epitope (SE) alleles (P = 9.4 x 10(-21)) were also associated with increased RA susceptibility. The genotypic associations were sustained among individuals who did not carry any SE alleles, except in the case of padi4&#95;104. Individuals carrying the risk SNPs and/or SE alleles were more susceptible to RA than were individuals carrying neither risk SNPs nor SE alleles., Conclusion: The PADI4 SNPs and haplotypes are associated with RA susceptibility in Koreans. Thus, the association of PADI4 with RA may depend on genetic heterogeneity between Asians and Europeans.

DNase II is an important enzyme for DNA fragmentation and degradation during programmed cell death and, consequently, a potential candidate gene for genetic study of systemic lupus erythematosus (SLE). Genetic associations of DNase II with SLE and related phenotypes were examined in Korean patients with SLE. A total of 350 Korean SLE patients and 330 healthy subjects were enrolled. Direct DNA sequencing and TaqMan were employed. Logistic regression analyses were performed to examine the genetic association with SLE and related phenotypes. Through direct sequencing in 24 Korean individuals, six sequence variants were identified: one in the 5' flanking region, four in exons (including one nonsynonymous), and one in the 3' flanking region. Four of these polymorphisms were selected for a larger-scale genotyping (350 SLE patients and 330 normal controls). No significant associations with the risk of SLE were detected. However, further analyses of association with the risk of renal disorder among SLE patients revealed several positive associations. One promoter SNP (-1066G>C), +2630T>C (Ser145Ser), +6235G>C and one haplotype showed weak associations with the risk of nephritis among SLE patients.

Objective: Substantial epidemiological and genetic evidence suggests that ankylosing spondylitis (AS) is likely due to an interplay of genetic and environmental factors. Recently, CARD15, located in chromosome 16q12, has been established as a disease susceptibility gene for Crohn's disease, Blau syndrome, and possibly psoriatic arthritis. Association studies in admixed populations from Northern European ancestry noted no such association between CARD15 mutations and AS. However, a homogenous population has yet to be studied. We investigated the prevalence of the 3 common CARD15 variants in a homogenous Korean population with AS., Methods: All subjects were native Koreans with AS satisfying the modified New York criteria. Korean controls were examined and confirmed to be unaffected by AS. Subjects with AS were genotyped for the R702W, G908R, and Leu1007fsinsC variants of CARD15 using mass array MALDI-TOF mass spectrometry., Results: A total of 205 AS subjects and 200 controls were genotyped. No subject with AS had any variants at the 702 and 1007 sites of CARD15. Only one subject was heterozygous for the 908 variant. The overall genotype frequency in AS for any CARD15 variant was 0.5%. No control had any of the 3 CARD15 variants., Conclusion: Our findings indicate that the CARD15 gene is not a major contributor to AS susceptibility in the Korean population.

The aim of our study was to develop a Korean rheumatic diseases-screening questionnaire. The questionnaire was constructed based on American College of Rheumatology criteria for rheumatic diseases and a connective tissue diseases screening questionnaire. Two groups of patients were selected and completed the questionnaire: (i) those with osteoarthritis (n=46), rheumatoid arthritis (n=52), systemic lupus erythematosus (n=50), scleroderma (n=8), polymyositis or dermatomyositis (n=7), Sjogren's disease (n=4), and mixed connective-tissue disease (n=9) as case subjects; and (ii) those with fibromyalgia (n=8) and general disease without evidence of any rheumatic disease (n=72) as controls. Laboratory results were analyzed for correlation with actual data using kappa (kappa) statistics. Test-retest reliability was performed in 12 patients, and showed strong agreement between the first and second interviews (kappa=0.91). The sensitivity of the questionnaire ranged from 77.8 to 100%, and specificity ranged from 68.8 to 95.0%. Negative predictive values were very high in the general population, from 98.4 to 99.99%. The kappa statistic for agreement between laboratory items was 0.22-0.56, except for rheumatoid factor, antinuclear antibody test, and muscle enzyme level. We have developed a simple and sensitive Korean rheumatic diseases-screening questionnaire for the epidemiologic study of rheumatic diseases in Korea.

High-dose intravenous immunoglobulins alter the disease activity of adult-onset Still's disease (AOSD). Because activation status of FcgammaR is possibly dependent on their genetic polymorphisms, we investigated whether the polymorphisms of FcgammaR IIa and IIIa are risk factors, and affect the clinical features of AOSD. Genomic DNA was extracted from 36 patients and from 197 healthy controls. Polymerase chain reaction for FcgammaR IIa and IIIa using the allele-specific primers and direct sequencing of FcgammaR IIIa polymorphic site were performed. The frequencies of FcgammaR IIa/IIIa genotype between patients with AOSD and controls were not different. The allelic frequencies of FcgammaR IIa/IIIa between patients with AOSD and controls were not different, either. However, the FcgammaR IIa-R/R131 genotype was associated with a higher concentration of hemoglobin (p=0.04) and stable liver function (p=0.009) than the other genotypes. The FcgammaR IIIa-F/F176 genotype was associated with significantly lower titers of serum ferritin (p=0.025), and higher serum albumin (p=0.037) and cholesterol (p=0.014) concentrations than the other genotypes. This study suggest that the FcgammaR IIa and IIIa polymorphisms might not be genetic risk factors for AOSD in Korean, but contribute to the activity of disease. FcgammaR IIa-R/R131 and IIIa-F/F176 genotypes, low-binding genotypes for IgG2a and G1, may have more protective effects in acute stage of the disease than the other genotypes.

Undifferentiated spondyloarthropathy (USpA) includes the forms that do not meet criteria for the established categories of spondyloarthropathy. The clinical spectrum of USpA is therefore wide and few studies have been published on USpA, especially peripheral arthritis. A total of 107 patients fulfilling the European Spondyloarthropathy Study Group criteria for SpA were studied retrospectively by a chart review and interview by a rheumatologist. Peripheral arthritis, excluding hip and shoulder involvement, occurred in 97 of the 107 patients (91%). Joint involvement tended to be monoarticular or pauciarticular, and most frequently developed in peripheral joints including the knee and ankle. Among the 97 patients with peripheral arthritis, only 37 (35%) had a persistent arthritis. HLA-B27 was detected in 80 patients (78%). Peripheral arthritis was found in the lower extremities regardless of symmetry or asymmetry and tended to run a benign course with only a few patients having persistent arthritis.