Polymorphisms in the ADRB2 gene and Graves disease: a case-control study and a meta-analysis of available evidence

Polymorphisms in Beta-2 Adrenergic Receptor Gene and Association with Tuberculosis

PURPOSE

Genetic susceptibility for tuberculosis in human has been previously demonstrated. Polymorphisms in genes involved in immune responses may alter the susceptibility of individuals to tuberculosis. Polymorphisms of beta-2 adrenergic receptor (ADRB2) gene can be possibly an important risk factor in tuberculosis. In this study, the association between rs1042713 (Arg16Gly +46A>G) and rs1042714 (Gln27Glu +79C>G) polymorphisms in ADRB2 gene and tuberculosis was evaluated.

METHODS

Genotype distributions of the rs1042713 (Arg16Gly +46A>G) and rs1042714 (Gln27Glu +79C>G) polymorphisms in ADRB2 gene in 106 patients with pulmonary tuberculosis and 88 healthy subjects were studied by PCR-RFLP method in an Iranian population.

RESULTS

The frequency of rs1042713*G and rs1042714*G alleles in ADRB2 gene in tuberculosis patients was significantly different from healthy controls [odds ratio (OR) 0.176, 95% confidence interval (CI) 0.065-0.48, P value <0.001 and OR 0.45, 95% CI 0.247-0.825, P value = 0.009, respectively]. There were no significant differences in haplotype analysis between the patients and control subjects.

CONCLUSION

The association was reported between rs1042713 and rs1042714 polymorphisms in ADRB2 gene and tuberculosis for the first time. rs1042713*G and rs1042714*G polymorphisms in ADRB2 gene makes people more susceptible to develop the disease.

Association of polymorphisms in the beta-2 adrenergic receptor gene with fracture risk and bone mineral density

Signaling through the beta-2 adrenergic receptor (B2AR) on the osteoblast influences bone remodeling in rodents. In the B2AR gene, three polymorphisms influence receptor function. We show that these polymorphisms are not associated with fracture risk or bone mineral density in the UCP, Rotterdam Study, and GEFOS cohorts.

INTRODUCTION

Signaling through the beta-2 adrenergic receptor (B2AR) on the osteoblast influences bone remodeling in rodents. In the B2AR gene, three polymorphisms are known to influence receptor function in vitro and in vivo (rs1042713, rs1042714, and rs1800888). We examined the role of these polymorphisms in the B2AR gene on human bone metabolism.

METHODS

We performed nested case-control studies to determine the association of these polymorphisms with fracture risk in the Utrecht Cardiovascular Pharmacogenetics (UCP) cohort and in three cohorts of the Rotterdam Study. We also determined the association of these polymorphisms with bone mineral density (BMD) in the GEFOS Consortium. UCP contains drug-dispensing histories from community pharmacies linked to national registrations of hospital discharges in the Netherlands. The Rotterdam Study is a prospective cohort study investigating demographics and risk factors of chronic diseases. GEFOS is a large international collaboration studying the genetics of osteoporosis. Fractures were defined by ICD-9 codes 800-829 in the UCP cohort (158 cases and 2617 unmatched controls) and by regular X-ray examinations, general practitioner, and hospital records in the Rotterdam Study (2209 cases and 8559 unmatched controls). BMD was measured at the femoral neck and lumbar spine using dual-energy X-ray absorptiometry in GEFOS (N = 32,961).

RESULTS

Meta-analysis of the two nested case-control studies showed pooled odds ratios of 0.98 (0.91-1.05, p = 0.52), 1.04 (0.97-1.12, p = 0.28), and 1.16 (0.83-1.62, p = 0.38) for the associations between rs1042713, rs1042714, and rs1800888 per minor allele and fractures, respectively. There were no significant associations of the polymorphisms and BMD in GEFOS.

CONCLUSION

In conclusion, polymorphisms in the beta-2 adrenergic receptor gene are not associated with fracture risk or BMD.

Effects of β2-adrenergic receptor gene polymorphisms on ritodrine therapy in pregnant women with preterm labor: prospective follow-up study

This study aimed to evaluate the effects of β2-adrenergic receptor (ADRB2) gene polymorphisms on ritodrine therapy outcomes in patients with preterm labor. Genotyping analysis of ADRB2 gene (rs1042713, rs1042714, rs1042717, rs1042718, and rs1042719) was performed on 137 patients with preterm labor. Survival analysis was conducted for the effects of SNPs on the median time to delivery as a primary outcome. The median time to delivery in the study patients was 349.3 h. Gestational age at admission and modified Bishop scores revealed significant effects on time to delivery (p < 0.001). Among studied SNPs, rs1042717 and rs1042718 showed linkage disequilibrium in this population, and their effects on time to delivery were marginally significant (p < 0.1). Patients with variant-homozygotes in the rs1042713 showed considerably shortened time to delivery compared to wild-allele carriers. The rs1042719 polymorphism significantly affected time to delivery in both univariate and multivariate analysis; the GC and CC carriers showed 64% decrease in time to delivery compared to the wild-type homozygote carriers. Based on the results, it was concluded that the gene polymorphisms of ADRB2 could affect ritodrine therapy in patients with preterm labor. However, given the single-center and the relatively small sample size, our hypothesis requires further independent validation using multi-center and large sample size.

The association of SCGB3A2 polymorphisms with the risk of Graves' disease: a meta-analysis

The aim of this study is to assess the association of the SCGB3A2 -112G>A promoter polymorphism with Graves' disease(GD) using a meta-analysis. Relevant studies were identified using PubMed and EMBASE electronic databases. A meta-analysis of relevant studies was performed. This meta-analysis included four case-control studies, containing 6,913 GD cases (Caucasian 3904, Han 3009) and 7,185 controls(Caucasian 4155, Han 3030). The combined results showed a significant difference in genotype distribution (-112A/G) between GD and control populations (A vs. G P = 1.53 × 10(-7); GG vs. AA+AG P = 6.78 × 10(-9)). Meta-analysis was performed using a fixed-effects model. Under the dominant model (GG/AA + GA), the AA and GA genotypes were significantly associated with GD (pooled OR = 1.24, 95 % CI 1.12-1.37). When the two European studies are combined, the AA and GA genotypes were also significantly associated with GD (pooled OR = 1.29, 95 % CI 1.20-1.39). This meta-analysis suggests that SCGB3A2 polymorphism at positions -112G>A was associated with GD both in Chinese and Caucasian population.

The associations between the polymorphisms in the CTLA-4 gene and the risk of Graves' disease in the Chinese population

Background

The associations between the polymorphisms in Cytotoxic T lymphocyte-associated molecule-4 (CTLA-4) gene and Graves’ disease (GD) have been extensively investigated in Chinese population. However, the results were inconsistent. The objective of this study is to investigate the associations between the polymorphisms in CTLA-4 gene and the risk of GD by meta-analysis.

Methods

We searched Pubmed database, Medline (Ovid) database, CNKI database and Wanfang database, covering all studies until August 11, 2012. Statistical analysis was performed by using the Revman4.2 software and the Stata10.0 software.

Results

A total of 28 case–control studies concerning the most widely studied three polymorphisms [+49A/G(rs231775), -318C/T(rs5742909) and CT60(rs3087243)] for Chinese population in 21 publications were included. The results suggested that the G allele carriers (GG+GA) might have an increased risk of GD when compared with the AA homozygote carriers for the +49A/G polymorphism (GG+GA vs. AA: OR = 2.57, 95%CI = 1.87-3.52). However, as to the -318C/T polymorphism and CT60 polymorphism, the results indicated that the variant allele carriers might have decreased risks of GD when compared with the homozygote carriers (−318C/T: TT+TC vs. CC: OR = 0.78, 95%CI = 0.62-0.97; CT60: AA+AG vs. GG: OR = 0.64, 95%CI = 0.52-0.78).

Conclusions

The current meta-analysis indicated that the polymorphisms in the CLTA-4 gene might be risk factors for GD in the Chinese population. In future, more large-scale case–control studies are needed to validate these results.

Graves' ophthalmopathy: a review of immunogenetics

Graves’ disease (GD) is the most common cause of thyrotoxicosis and often involves the orbits. Graves’ ophthalmopathy (GO), also known as Thyroid Eye Disease (TED), can be clinically significant and advance to sight-threatening stages. Our knowledge of the immunogenetic pathophysiology of GO is rapidly expanding. The present review is an attempt to summarize the current state of knowledge on the immunogenetics of GO. First we briefly review the epidemiology and clinical importance of GO, and then we describe in detail the macromolecular pathogenesis and finally immunogenetics of GO. Discrepancies between the results from various reports and the limitations of the available data are discussed. In particular, there is a scarcity of data from non-Asian populations. While several studies have demonstrated significant associations between polymorphisms in certain genes (especially CTLA-4, HLA-DRB-1, and TNF-α), there is a need for studies that investigate the relationship between polymorphisms and both serum and local concentrations of the resulting proteins. A complete understanding of GO susceptibility and pathogenesis has not been yet possible due to a number of important knowledge gaps that need to be filled by future research.

The genetic basis of graves' disease

The presented comprehensive review of current knowledge about genetic factors predisposing to Graves’ disease (GD) put emphasis on functional significance of observed associations. In particular, we discuss recent efforts aimed at refining diseases associations found within the HLA complex and implicating HLA class I as well as HLA-DPB1 loci. We summarize data regarding non-HLA genes such as PTPN22, CTLA4, CD40, TSHR and TG which have been extensively studied in respect to their role in GD. We review recent findings implicating variants of FCRL3 (gene for FC receptor-like-3 protein), SCGB3A2 (gene for secretory uteroglobin-related protein 1- UGRP1) as well as other unverified possible candidate genes for GD selected through their documented association with type 1 diabetes mellitus: Tenr–IL2–IL21, CAPSL (encoding calcyphosine-like protein), IFIH1(gene for interferon-induced helicase C domain 1), AFF3, CD226 and PTPN2. We also review reports on association of skewed X chromosome inactivation and fetal microchimerism with GD. Finally we discuss issues of genotype-phenotype correlations in GD.

Immunogenetic mechanisms leading to thyroid autoimmunity: recent advances in identifying susceptibility genes and regions

The autoimmune thyroid diseases (AITD) include Graves’ disease (GD) and Hashimoto’s thyroiditis (HT), which are characterised by a breakdown in immune tolerance to thyroid antigens. Unravelling the genetic architecture of AITD is vital to better understanding of AITD pathogenesis, required to advance therapeutic options in both disease management and prevention. The early whole-genome linkage and candidate gene association studies provided the first evidence that the HLA region and CTLA-4 represented AITD risk loci. Recent improvements in; high throughput genotyping technologies, collection of larger disease cohorts and cataloguing of genome-scale variation have facilitated genome-wide association studies and more thorough screening of candidate gene regions. This has allowed identification of many novel AITD risk genes and more detailed association mapping. The growing number of confirmed AITD susceptibility loci, implicates a number of putative disease mechanisms most of which are tightly linked with aspects of immune system function. The unprecedented advances in genetic study will allow future studies to identify further novel disease risk genes and to identify aetiological variants within specific gene regions, which will undoubtedly lead to a better understanding of AITD patho-physiology.

The I/D polymorphism of angiotensin-converting enzyme gene in major depressive disorder and therapeutic outcome: a case-control study and meta-analysis

BACKGROUND

The insertion/deletion (I/D) polymorphism of angiotensin-converting enzyme (ACE) gene has been implicated in susceptibility to major depressive disorder (MDD) and its treatment response; however, a large number of studies have reported inconsistent results. The aim of this study is to examine the role of I/D polymorphism of ACE gene in MDD risk and its treatment response by a case-control study and meta-analysis.

METHODS

Three hundred and sixty eight depressed patients who met DSM-IV criteria for major depressive disorder and 371 normal controls were recruited for the study. We searched Pubmed, Embase, CNKI, Wanfang, and Weipu database, covering all papers until March 31, 2011. Statistical analysis was performed using the software STATA 10.0.

RESULTS

Genotype and allele distributions of ACE I/D were not significantly different between case and control groups. No significant association with treatment response was discovered. A total of 2479 cases and 7744 controls in 15 case-control studies were included in this meta-analysis. The results indicated that the D/D homozygote carriers had an 18% increased risk of MDD, when compared with the homozygotes I/I and heterozygote I/D [odds ratio (OR)=1.18, 95% confidence interval (CI):1.04-1.33]. In the subgroup analysis, significant elevated risks were associated with D/D homozygote carriers in Caucasians (OR=1.20 and 95% CI: 1.04-1.38 for D/D vs I/D+I/I) but not in Asians. Moderate trends of an increased risk in the D allele carriers from total sample (OR, 1.15; 95% CI: 1.02-1.30) was also observed. The D/D homozygote carriers were associated with a 28% increased risk of MDD relative to the homozygotes I/I (OR 1.28; 95% CI: 1.11-1.49). In subgroup analysis, Caucasians showed significant association (OR 1.30; 95% CI: 1.09-1.56). No association was found in the Asian groups. No publication bias was observed in this meta-analysis by using the Egger method.

CONCLUSIONS

The ACE I/D polymorphism is not associated with MDD and its treatment response in a Chinese case-control study. Meta-analysis evidence suggests that the I/D polymorphism of ACE gene may be a risk factor of major depressive disorder in Caucasians.

The pharmacogenetics and pharmacogenomics of asthma therapy

Despite the availability of several classes of asthma medications and their overall effectiveness, a significant portion of patients fail to respond to these therapeutic agents. Evidence suggests that genetic factors may partly mediate the heterogeneity in asthma treatment response. This review discusses important findings in asthma pharmacogenetic and pharmacogenomic studies conducted to date, examines limitations of these studies and, finally, proposes future research directions in this field. The focus will be on the three major classes of asthma medications: β-adrenergic receptor agonists, inhaled corticosteroids and leukotriene modifiers. Although many studies are limited by small sample sizes and replication of the findings is needed, several candidate genes have been identified. High-throughput technologies are also allowing for large-scale genetic investigations. Thus, the future is promising for a personalized treatment of asthma, which will improve therapeutic outcomes, minimize side effects and lead to a more cost-effective care.

The -112G>A polymorphism of the secretoglobin 3A2 (SCGB3A2) gene encoding uteroglobin-related protein 1 (UGRP1) increases risk for the development of Graves' disease in subsets of patients with elevated levels of immunoglobulin E

The human secretoglobin 3A2 (SCGB3A2) gene encoding secretory uteroglobin-related protein 1 (UGRP1) resides on the chromosome region 5q31-33 that harbors a susceptibility locus to several autoimmune and inflammatory diseases, including asthma and Graves' disease (GD). Recently, association between the marker rs1368408 (-112G >A), located in the promoter region of the SCGB3A2 gene, and susceptibility to GD was found in Chinese and UK Caucasians. The study aim was to evaluate whether this polymorphism confers GD susceptibility in a large population cohort comprising 1,474 Russian GD patients and 1,619 controls. The marker rs1368408 was studied using a TaqMan allele discrimination assay. Serum levels of UGRP1 and immunoglobulin E (IgE) were assessed using enzyme-linked immunosorbent assay (ELISA) analyses. Association between the allele A of SCGB3A2 and a higher risk of GD (odds ratio [OR] = 1.33, P = 2.9 × 10(-5)) was shown. Both affected and non-affected carriers of the higher risk genotype A/A had significantly decreased levels of serum UGRP1 compared to the subjects homozygous for G/G (93 ± 37 pg/ml vs. 132 ± 45 pg/ml, P = 0.0011 for GD patients; 77 ± 28 pg/ml vs. 119 ± 33 pg/ml, P = 0.0019 for controls). Serum IgE levels were significantly higher in non-affected subjects homozygous for A/A compared to control individuals homozygous for G/G (153 ± 46 IU/ml vs. 122 ± 40 IU/ml, P = 0.0095). Our data suggest that the carriage of the SCGB3A2 -112A/A variant increases the risk for GD in subsets of patients with elevated levels of IgE, a hallmark of allergic asthma. Therefore, the SCGB3A2 -112G >A polymorphism may be considered as a likely marker linking susceptibility to allergy/asthma and GD on chromosome 5q31-33.

Confirmation of association of chromosome 5q31-33 with United Kingdom Caucasian Graves' disease

BACKGROUND

Previous genome-wide microsatellite screening in Graves' disease (GD) has suggested several regions of linkage to disease. Although replication has been inconsistent, some regions such as chromosome 5q31-33 have been associated with several Oriental GD patient cohorts. Recently, two studies have reported association of single-nucleotide polymorphism (SNP) rs31480 in interleukin 3 (IL-3) and the rs1368408 and SNP75 (-623 approximately -622 AG/-T) SNPs in secretoglobulin family 3a member 2 (SCGB3A2) with GD and suggested that this may account for linkage to the 5q31-33 region in Oriental GD datasets. We sought to confirm this association in a large Caucasian U.K. GD cohort.

METHODS

The rs31480 SNP was shown to tag all known common variations in IL-3 and the rs1368408 SNP was shown to tag all common variations in SCGB3A2. The SCGB3A2 SNP75 was found to be rare in the U.K. Caucasian population and, therefore, was not screened. We genotyped rs31480 and rs1368408 and performed a case-control association study in 2504 GD cases and 2688 controls from the U.K.

RESULTS

Association between the SCGB3A2 rs1368408 SNP and GD was detected (p = 0.007, odds ratio = 1.18, 95% confidence intervals = 1.05-1.33). No association between the IL-3 rs31804 SNP and U.K. Caucasian GD patients was observed.

CONCLUSIONS

These data suggest that chromosome 5q31-q33 contains a susceptibility locus for Caucasian GD patients as well as Oriental GD patients. Although association was detected between SCGB3A2 and U.K. Caucasian GD subjects, the size of effect was smaller than that seen in the Oriental population (odds ratio = 1.28-1.73). Fine mapping within this region will be required to determine the exact location of the etiological variants present within this region for both Caucasian and Oriental GD patients.