Association of estrogen receptor alpha and interleukin-10 gene polymorphisms with endometriosis in a Chinese population. Fertil Steril. 2009;92:54-60. [PMID: 18687423 DOI: 10.1016/j.fertnstert.2008.04.069]

Association between polymorphisms of cytokine genes and endometriosis: A comprehensive systematic review and meta-analysis

INTRODUCTION

There is abundant evidence to suggest that cytokines play a part in the mechanisms responsible for the formation of endometrium heterotopy. Cytokine synthesis is not only determined by the body's immunological reactivity but also by polymorphisms in the immune regulatory genes. The study of these polymorphisms in the immune regulatory genes offers up new possibilities in terms of prognosticating the risk of endometriosis and susceptibility to its treatment. The purpose of this comprehensive systematic review and meta-analysis was to investigate whether or not cytokine gene polymorphisms were linked to an increased chance of endometriosis.

METHODS

By searching MEDLINE, Scopus, and Web of Science databases, the relevant studies were identified. The odds ratio (OR) with 95% confidence interval (CI) was used to assess the association between TNF-α/IL-10/IL-6/TGF-β/IFN-γ/IL-1β gene polymorphisms and endometriosis risk.

RESULTS

A total of 5128 cases and 5334 controls in 32 eligible studies were included in the meta-analysis. Overall, results indicated the negative association between the cytokine gene polymorphisms and endometriosis in the dominant model of TNF-α (rs1799964): [OR] = 0.64, [CI]: 0.46-0.89) and a positive association in IFN-γ a13 allele: OR= 1.45, [CI]: 1.07-1.98; and IL-10 (rs1800872): [OR]= 1.60, [CI]: 1.21-2.12).

CONCLUSION

The present study suggests that IL-10 (rs1800872) and IFN-γ a13 allele may be a risk factors for endometriosis. Also, TNF-α (rs1799964) is associated with decreased susceptibility to endometriosis.

How Do Microorganisms Influence the Development of Endometriosis? Participation of Genital, Intestinal and Oral Microbiota in Metabolic Regulation and Immunopathogenesis of Endometriosis

Microorganisms inhabiting the human body play an extremely key role in its proper functioning, as well as in the development of the immune system, which, by maintaining the immune balance, allows you to enjoy health. Dysbiosis of the intestinal microbiota, or in the oral cavity or reproductive tract, understood as a change in the number and diversity of all microorganisms inhabiting them, may correlate with the development of many diseases, including endometriosis, as researchers have emphasized. Endometriosis is an inflammatory, estrogen-dependent gynecological condition defined by the growth of endometrial cells outside the uterine cavity. Deregulation of immune homeostasis resulting from microbiological disorders may generate chronic inflammation, thus creating an environment conducive to the increased adhesion and angiogenesis involved in the development of endometriosis. In addition, research in recent years has implicated bacterial contamination and immune activation, reduced gastrointestinal function by cytokines, altered estrogen metabolism and signaling, and abnormal progenitor and stem cell homeostasis, in the pathogenesis of endometriosis. The aim of this review was to present the influence of intestinal, oral and genital microbiota dysbiosis in the metabolic regulation and immunopathogenesis of endometriosis.

Sex hormone-related polymorphisms in endometriosis and migraine: A narrative review

Some evidence indicates endometriosis and migraine have a common genetic predisposition in sex-hormone genes, which could have important implications for the treatment of these two heterogenous conditions. To date, the genes responsibility remains unknown. Based on the biological hypothesis that polymorphisms of genes involved in sex-hormone pathways may influence estrogen levels and phenotypes of both disorders, we did a literature search for candidate sex-hormone genes and genes involved in the metabolism of estradiol. The aim was to review the evidence for shared sex-hormone-related polymorphisms between endometriosis and migraine and provide an exhaustive overview of the current literature. We included case-control studies investigating associations between candidate sex-hormone-related genes and the disorders endometriosis and migraine, respectively. Results showed three overlapping sex-hormone-associated polymorphisms in estrogen receptor genes that are associated with both conditions. To confirm possible associations with other sex-hormone genes, larger studies are needed.

Genetic risk factors for endometriosis near estrogen receptor 1 and coexpression of genes in this region in endometrium

The etiology and pathogenesis of endometriosis are complex with both genetic and environmental factors contributing to disease risk. Genome-wide association studies (GWAS) have identified multiple signals in the estrogen receptor 1 (ESR1) region associated with endometriosis and other reproductive traits and diseases. In addition, candidate gene association studies identified signals in the ESR1 region associated with endometriosis risk suggesting genetic regulation of genes in this region may be important for reproductive health. This study aimed to investigate hormonal and genetic regulation of genes in the ESR1 region in human endometrium. Changes in serum oestradiol and progesterone concentrations and expression of hormone receptors ESR1 and progesterone receptor (PGR) were assessed in endometrial samples from 135 women collected at various stages of the menstrual cycle. Correlation between hormone concentrations, receptor expression and expression of genes in the ESR1 locus was investigated. The effect of endometriosis risk variants on expression of genes in the region was analyzed to identify gene targets. Hormone concentrations and receptor expression varied significantly across the menstrual cycle. Expression of genes in the ESR1 region correlated with progesterone concentration; however, they were more strongly correlated with expression of ESR1 and PGR suggesting coregulation of genes. There was no evidence that endometriosis risk variants directly regulated expression of genes in the region. Limited sample size and cellular heterogeneity in endometrial tissue may impact the ability to detect significant genetic effects on gene expression. Effects of these variants should be validated in a larger dataset and in relevant individual cell types.

Evaluating the Association Between Dental Fluorosis and Polymorphisms in Bone Development and Mineralization Genes Among Population from a Fluoride Endemic Region of Eastern India

Close to 12 million people in India are affected by more than the desirable level of fluoride in drinking water that could lead to dental, skeletal, and non-skeletal fluorosis. Dental fluorosis is a developmental defect that results in hypo-mineralization and pronounced porosity of enamel in the affected individuals. As estrogen receptor 1 (ESR1), collagen type 1 alpha 2 (COL1A2), bone γ-carboxyglutamic acid protein (BGLAP), and secreted protein acidic and cysteine rich (SPARC) genes are involved in bone development and mineralization, polymorphisms in these genes could be determining factors in influencing the risk to fluorosis among the exposed individuals in fluoride endemic areas. A case-control study was carried out among a total of 87 individuals (case = 36, control = 51) to examine the association between selected polymorphisms in the ESR1, COL1A2, BGLAP, and SPARC genes and risk of dental fluorosis from a fluoride endemic region of Eastern India. Altogether, 10 single nucleotide polymorphisms (SNPs) in ESR1 (rs2234693, rs2228480, rs3798577, rs2077647, and rs9340799), COL1A2 (rs42524, rs412777), BGLAP (rs1800247), and SPARC (rs6579885, rs4958278) genes were genotyped through PCR-RFLP in these subjects. The association of the SNPs for disease risk estimation was measured by odds ratio with 95% confidence interval. The risk genotypes of none of the 10 SNPs showed statistically significant association with risk of dental fluorosis. Frequencies of the haplotypes in the intragenic SNPs of the ESR1, COL1A2, and SPARC genes did not reveal any statistically significant difference between the case and control groups. The present study is the first of its kind from India that has attempted to investigate possible involvement of genetic factors in influencing the risk to fluorosis among the population from a fluoride endemic region.

Polymorphisms and endometriosis: a systematic review and meta-analyses

BACKGROUND

Endometriosis is an estrogen-dependent gynecological disorder that affects at least 10% of women of reproductive age. It may lead to infertility and non-specific symptoms such as chronic pelvic pain. Endometriosis screening and diagnosis are difficult and time-consuming. Late diagnosis (with a delay ranging from 3.3 to 10.7 years) is a major problem and may contribute to disease progression and a worse response to treatment once initiated. Efficient screening tests might reduce this diagnostic delay. As endometriosis is presumed to be a complex disease with several genetic and non-genetic pathogenic factors, many researchers have sought to identify polymorphisms that predispose to this condition.

OBJECTIVE AND RATIONALE

We performed a systematic review and meta-analysis of the most regularly reported polymorphisms in order to identify those that might predispose to endometriosis and might thus be of value in screening.

SEARCH METHODS

The MEDLINE database was searched for English-language publications on DNA polymorphisms in endometriosis, with no date restriction. The PubTator text mining tool was used to extract gene names from the selected publications' abstracts. We only selected polymorphisms reported by at least three studies, having applied strict inclusion and exclusion criteria to their control populations. No stratification based on ethnicity was performed. All steps were carried out according to PRISMA guidelines.

OUTCOMES

The initial selection of 395 publications cited 242 different genes. Sixty-two genes (corresponding to 265 different polymorphisms) were cited at least in three publications. After the application of our other selection criteria (an original case-control study of endometriosis, a reported association between endometriosis and at least one polymorphism, data on women of reproductive age and a diagnosis of endometriosis in the cases established by surgery and/or MRI and confirmed by histology), 28 polymorphisms were eligible for meta-analysis. Only five of the 28 polymorphisms were found to be significantly associated with endometriosis: interferon gamma (IFNG) (CA) repeat, glutathione S-transferase mu 1 (GSTM1) null genotype, glutathione S-transferase pi 1 (GSTP1) rs1695 and wingless-type MMTV integration site family member 4 (WNT4) rs16826658 and rs2235529. Six others showed a significant trend towards an association: progesterone receptor (PGR) PROGINS, interCellular adhesion molecule 1 (ICAM1) rs1799969, aryl-hydrocarbon receptor repressor (AHRR) rs2292596, cytochrome family 17 subfamily A polypeptide 1 (CYP17A1) rs743572, CYP2C19 rs4244285 and peroxisome proliferator-activated receptor gamma (PPARG) rs1801282), and 12 showed a significant trend towards the lack of an association: tumor necrosis factor (TNF) rs1799964, interleukin 6 (IL6) rs1800796, transforming growth factor beta 1 (TGFB1) rs1800469, estrogen receptor 1 (ESR1) rs2234693, PGR rs10895068, FSH receptor (FSHR) rs6166, ICAM1 rs5498, CYP1A1 rs4646903, CYP19A1 rs10046, tumor protein 53 (TP53) rs1042522, X-ray repair complementing defective repair in Chinese hamster cells 1 (XRCC1) rs25487 and serpin peptidase inhibitor clade E member 1 (SERPINE1) rs1799889; however, for the 18 polymorphisms identified in the latter two groups, further studies of the potential association with the endometriosis risk are needed. The remaining five of the 28 polymorphisms were not associated with endometriosis: glutathione S-transferase theta 1 (GSTT1) null genotype, vascular endothelial growth factor alpha (VEGFA) rs699947, rs833061, rs2010963 and rs3025039.

WIDER IMPLICATIONS

By carefully taking account of how the control populations were defined, we identified polymorphisms that might be candidates for use in endometriosis screening and polymorphisms not associated with endometriosis. This might constitute the first step towards identifying polymorphism combinations that predispose to endometriosis (IFNG (CA) repeat, GSTM1 null genotype, GSTP1 rs1695, WNT4 rs16826658 and WNT4 rs2235529) in a large cohort of patients with well-defined inclusion criteria. In turn, these results might improve the diagnosis of endometriosis in primary care. Lastly, our present findings may enable a better understanding of endometriosis and improve the management of patients with this disease.

Anti-inflammatory cytokines in endometriosis

Although the pathogenesis of endometriosis is not fully understood, it is often considered to be an inflammatory disease. An increasing number of studies suggest that differential expression of anti-inflammatory cytokines (e.g., interleukin-4 and -10, and transforming growth factor-β1) occurs in women with endometriosis, including in serum, peritoneal fluid and ectopic lesions. These anti-inflammatory cytokines also have indispensable roles in the progression of endometriosis, including by promoting survival, growth, invasion, differentiation, angiogenesis, and immune escape of the endometriotic lesions. In this review, we provide an overview of the expression, origin, function and regulation of anti-inflammatory cytokines in endometriosis, with brief discussion and perspectives on their future clinical implications in the diagnosis and therapy of the disease.

Association of genetic polymorphisms of estrogen and progesterone receptors and endometriosis: Meta-analysis

Purpose:

To investigate the association between polymorphisms in the genes of estrogen receptor alpha, estrogen receptor beta, and progesterone receptor and the genesis of endometriosis.

Methods:

Systematic review and meta-analysis of articles published fully in the PubMed database, in Portuguese, English, or Spanish, from 2006 to 2017, using the descriptors: “endometriosis,” “polymorphism,” “ESR1,” “ESR2,” “PROGINS,” “rs9340799,” “rs4986938,” and “rs1042838.”

Results:

A total of 20 studies were included based on the criterion of search for susceptibility to endometriosis related to polymorphisms of estrogen receptor alpha, estrogen receptor beta, and progesterone receptor genes. Analysis of all polymorphisms found no association with endometriosis.

Conclusion:

This meta-analysis showed that estrogen receptor alpha, estrogen receptor beta, and progesterone receptor polymorphisms are not related to susceptibility to endometriosis. However, such results may be able to provide more detailed interpretations of how they influence the pathogenesis of endometriosis.

A current view of the role of epigenetic changes in the aetiopathogenesis of endometriosis

The purpose of the study was to examine the role of epigenetic changes in the aetiopathogenesis of endometriosis. The analysis and review of the relevant current literature in English language related to the role of epigenetic changes in the aetiopathogenesis of endometriosis. Epigenetic changes are common denominators for hormonal, immunological and inflammatory aberrations which play a key role in the aetiopathogenesis of endometriosis. Many internal and external factors may cause the different running of the epigenetic mechanism. As yet fully unknown genetic factors may increase the sensitivity of the epigenetic mechanism to various internal and external factors. The breakdown of epigenetic regulation is the main factor initiating the pathogenetic mechanisms for endometriosis formation.

The prognostic value of IL10 and TNF alpha functional polymorphisms in premenopausal early-stage breast cancer patients

BACKGROUND

Interleukin-10 and tumor necrosis factor α play an important role in breast carcinogenesis. Genes, encoding those two cytokines, contain single nucleotide polymorphisms, which are associated with differential levels of gene transcription. This study analyzes single nucleotide polymorphisms in interleukin 10 and tumor necrosis factor α genes and their contribution to breast cancer phenotype, lymph node status and survival in a group of young Lithuanian women with early-stage breast cancer patients.

RESULTS

We genotyped 100 premenopausal Eastern European (Lithuanian) patients with stage I-II breast cancer, ≤ 50 years old at the time of diagnosis, for interleukin 10 -592A > C, -819C > T and -1082A > G and tumor necrosis factor α -308G > A single nucleotide polymorphisms in the gene promoter region. We used the polymerase chain reaction, namely a restriction fragment length polymorphism method, for a SNP analysis. All genotypes were in Hardy-Weinberg equilibrium and had the same distribution as the HapMap CEU population. Holders of IL10 -592A > C heterozygous IL10 -592 AC genotype had a higher probability of estrogen receptor positive breast cancer phenotype than homozygous variants (P = 0.017). Phased ACC haplotype of IL10 polymorphisms was associated with younger age of diagnosis (P = 0.017). Of all the tested single nucleotide polymorphisms, only TNFα -308G > A has revealed a prognostic capability for breast cancer survival. GA genotype carriers, compared to GG, showed a significant disadvantage in progression-free survival (P = 0.005, adjusted hazard ratio (HR) = 4.631, 95 % confidence interval (CI) = 1.587 - 13.512), metastasis-free survival (P = 0.010, HR = 4.708, 95 % CI = 1.445 - 15.345) and overall survival (P = 0.037, HR = 4.829, 95 % CI = 1.098 - 21.243).

CONCLUSIONS

According to our data, IL10 -1082A > G, -819 T > C, -592A > C polymorphisms and phased haplotypes have not revealed a prognostic value for breast cancer. On the contrary, the TNFα -308 polymorphism might modulate the risk and contribute to the identification of patients at a higher risk of breast cancer recurrence, metastasis and worse overall survival among young Lithuanian early-stage breast cancer patients.

The estrogen receptor α gene (XbaI, PvuII) polymorphisms and susceptibility to idiopathic scoliosis: a meta-analysis

STUDY DESIGN

A genetic association meta-analysis of estrogen receptor α gene (ERα) polymorphisms with idiopathic scoliosis.

OBJECTIVE

To determine whether the ERα gene polymorphisms correlate with idiopathic scoliosis. Idiopathic scoliosis represents a complex genetic trait under the influence of multiple predisposition genes. Several studies showed that single nucleotide polymorphism (SNP) in ERα was associated with idiopathic scoliosis, but the results from some studies were conflicting.

METHODS

We searched PubMed, EMBASE, and Cochrane CENTRAL databases from January 1994 to January 2014. All the case-control studies included should mainly study the relationship between XbaI A/G, PvuII T/C polymorphisms and the susceptibility of idiopathic scoliosis.

RESULTS

A total of 299 articles were found, six of which fulfilled the inclusion criteria after being assessed by two reviewers. A pooled odds ratio (OR) with 95% confidence interval (95% CI) was calculated to assess the associations. Subgroup meta-analyses were performed according to ethnicity. Overall, ERα Xbal A/G polymorphism was not associated with risk of idiopathic scoliosis (G versus A, OR 1.07, 95% CI 0.88-1.30, P = 0.51; AG versus AA, OR 1.03, 95% CI 0.89-1.21, P = 0.67; GG versus AA, OR 1.12, 95% CI 0.72-1.73, P = 0.61; AG/GG versus AA, OR 1.05, 95% CI 0.91-1.22, P = 0.49; GG versus AG/AA, OR 1.10, 95% CI 0.75-1.63, P = 0.62). ERα PvuII T/C polymorphism was also not associated with risk of idiopathic scoliosis under five models (C versus T, OR 0.93, 95% CI 0.75-1.14, P = 0.48; TC versus TT, OR 0.99, 95% CI 0.80-1.23, P = 0.93; CC versus TT, OR 1.05, 95% CI 0.80-1.39, P = 0.72; TC/CC versus TT, OR 1.01, 95% CI 0.83-1.23, P = 0.93; CC versus TC/TT, OR 1.05, 95% CI 0.82-1.33, P = 0.72).

CONCLUSION

ERα Xbal and ERα PvuII polymorphisms are not obviously associated with risk of idiopathic scoliosis.

Relationship between IL-10 promoter gene polymorphisms and plasma level and susceptibility to overlap syndrome of diarrhea irritable bowel syndrome and functional dyspepsia

AIM: To investigate the relationship between interleukin-10 (IL-10) promoter gene polymorphisms and plasma levels and susceptibility to overlap syndrome of diarrhea irritable bowel syndrome (D-IBS) and functional dyspepsia (FD).

METHODS: Blood samples were collected from 164 patients and 200 healthy controls and genomic DNA was extracted. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to determine the genotypes in the -592A/C site, and amplification refractory mutation system polymerase chain reactions (ARMS-PCR) and DNA sequencing were performed to detect the polymorphism of the -1082G/A site. IL-10 plasma levels were determined by enzyme-linked immunosorbent assay (ELISA).

RESULTS: The -592A/C site in the IL-10 gene showed no significant differences in genotypes or allele frequency between the D-IBS-FD overlap syndrome group and control group, but the frequency of -592 CC genotype was significantly decreased in the D-IBS-FD overlap syndrome group. Compared with the CC genotype, the AA genotype and the AA+AC genotypes increased the risk of D-IBS-FD overlap syndrome 1.989 and 1.808 times, respectively. There were no significant differences in the distribution or the allele frequency of -1082 genotypes, the genotypes of the combination of -592 and -1082, and the distribution of the genotypes of different IL-10 levels between the D-IBS-FD overlap syndrome and healthy control groups. The average plasma IL-10 levels were significantly lower in patients with D-IBS-FD overlap syndrome than in healthy controls (14.60 pg/mL ± 7.14 pg/mL vs 22.86 pg/mL ± 10.62 pg/mL, P < 0.001). Among patients with D-IBS-FD overlap syndrome, the average plasma IL-10 levels in patients with -592 AA, -592 AC, -592 CC, and -592 AA+AC genotypes were 14.50 pg/mL ± 6.37 pg/mL, 14.85 pg/mL ± 7.75 pg/mL, 13.92 pg/mL ± 7.63 pg/mL, 14.68 pg/mL ± 7.10 pg/mL, respectively, which showed no significant differences. Plasma IL-10 levels showed no significant difference between the carriers of A allele and non-carriers.

CONCLUSION: The -592A site in IL-10 gene promoter and lower IL-10 plasma level may be associated with susceptibility to overlap syndrome of D-IBS and FD, but there is no association between them.

ESR1 rs9340799 is associated with endometriosis-related infertility and in vitro fertilization failure

Estrogen receptor alpha has a central role in human fertility by regulating estrogen action in all human reproductive tissues. Leukemia inhibitory factor (LIF) expression, a cytokine critical for blastocyst implantation, is mediated by estrogen signaling, so we hypothesized that ESR1 gene polymorphisms might be candidate risk markers for endometriosis-related infertility and in vitro fertilization (IVF) failure. We included 98 infertile women with endometriosis, 115 infertile women with at least one IVF failure and also 134 fertile women as controls. TaqMan SNP assays were used for genotyping LIF (rs929271), MDM2 (rs2279744), MDM4 (rs1563828), USP7 (rs1529916), and ESR1 (rs9340799 and rs2234693) polymorphisms. The SNP ESR1 rs9340799 was associated with endometriosis-related infertility (P < 0.001) and also with IVF failure (P = 0.018). After controlling for age, infertile women with ESR1 rs9340799 GG genotype presented 4-fold increased risk of endometriosis (OR 4.67, 95% CI 1.84–11.83, P = 0.001) and 3-fold increased risk of IVF failure (OR 3.33, 95% CI 1.38–8.03, P = 0.007). Our results demonstrate an association between ESR1 rs9340799 polymorphism and infertile women with endometriosis and also with women who were submitted to IVF procedures and had no blastocyst implantation.

Serum level of IL-10 is increased in patients with endometriosis, and IL-10 promotes the growth of lesions in a murine model

Immune dysregulation may be involved in the development of endometriosis. The anti-inflammatory cytokine IL-10 plays an important role in eliminating unwanted cells and cellular debris in a silent way. We investigated the modulatory role of IL-10 in the development of endometriosis. We observed that the serum level of IL-10 in patients with endometriosis was significantly higher than that in healthy subjects or in control subjects with other gynecological disease. Monocyte-derived dendritic cells acquired from male donors and subsequently conditioned with serum from women with endometriosis exhibited a tolerogenic phenotype, including increased IL-10 production, lower IL-12 secretion, and down-regulation of CD86 and HLA-DR molecules. Depletion of IL-10 activity in a C57BL/6 mouse model of surgically induced endometriosis significantly decreased the size of endometrial lesions. In contrast, IL-10 administration promoted the growth of endometrial lesions in this model. In addition, infiltrated plasmacytoid dendritic cells were the primary IL-10-secreting immune cells in endometrial lesions. Our findings suggest that IL-10 may suppress immunity against endometrial implants, contributing to development of endometriosis.

Association between interleukin-10 promoter polymorphisms and endometriosis: a meta-analysis

To investigate the influence of the interleukin-10 gene promoter polymorphisms on the susceptibility of endometriosis, we examined the association by performing a meta-analysis. The PubMed, Embase, HuGE Navigator and CNKI were searched to identify eligible studies. We then conducted a meta-analysis to examine the association between interleukin-10 gene promoter polymorphisms and endometriosis. Eight case-control studies which examined the association between the IL-10 gene promoter polymorphisms and the susceptibility to endometriosis were finally included in the meta-analysis. Meta-analysis of the IL-10 -592 A/C polymorphisms showed a significant increased risk of endometriosis in the overall and Asian population in all genetic models and allele contrast. However, meta-analysis of the IL-10 -1082 A/G and IL-10 -819 T/C polymorphisms showed no association with endometriosis in all genetic models and allele contrast in the overall and Asian population samples. In addition, there was not a significant association between the IL-10 -592 A/C gene promoter polymorphisms with the severity of endometriosis. In conclusion, this meta-analysis suggests that the IL-10 -592 A/C polymorphisms conferred susceptibility to endometriosis. However, no associations were found between the IL-10 -1082 A/G and -819 T/C polymorphisms and susceptibility to endometriosis. Further studies are required to elucidate these associations more clearly.

Insights into Assessing the Genetics of Endometriosis

Endometriosis is a complex disease arising from the interplay between multiple genetic and environmental factors. The genetic variants potentially underlying the hereditary component of endometriosis have been widely investigated through hypothesis-driven candidate gene studies, an approach that generally has proven to be inherently difficult and problematic for a number of reasons. Recently, through major collaborative efforts in the endometriosis research field, hypothesis-free genome-wide approaches have started to provide new insights into potential pathways leading to development of endometriosis, as well as highlighting the phenotypic heterogeneity of the condition. This review summarizes the most recent studies investigating the genetic variation contributing to endometriosis, with a particular focus on genome-wide approaches, and discusses promising future directions of genetic research.

Estrogen receptor-alpha gene PvuII (T/C) and XbaI (A/G) polymorphisms and endometriosis risk: a meta-analysis

Estrogen receptor-alpha (ER-α) polymorphisms have been hypothesized to be associated with the risk of endometriosis (EMT) development by many epidemiological studies, however, the available results were conflicting. To derive a more precise estimation of association between the ER-α PvuII (T/C) and XbaI (A/G) polymorphisms and risk of EMT, we performed a meta-analysis. Summary odds ratios (ORs) and 95% confidence intervals (95% CIs) for ER-α polymorphisms and EMT were calculated in a fixed-effects model and a random-effects model when appropriate. This meta-analysis included 20 case-control studies with 1752 cases and 1742 controls for PvuII polymorphism and 15 case-control studies with 1349 cases and 1411 controls for XbaI polymorphism. For PvuII T/C polymorphism, no obvious associations were found for all genetic models when all studies were pooled into the meta-analysis. In the subgroup analyses by ethnicity, country, HWE in controls and study sample size, a significantly increased risk was observed among Caucasians (recessive model, OR=2.56, 95% CI=1.06-6.16) and among studies without the HWE (recessive model, OR=1.85, 95% CI=1.20-2.84). For XbaI A/G polymorphism, also no obvious associations were found for all genetic models. In the subgroup analyses by ethnicity, country, HWE in controls and study sample size, still no obvious associations were found. No publication bias was found in the present study. This meta-analysis suggests that ER-α gene PvuII (T/C) and XbaI (A/G) polymorphisms may not be associated with EMT risk, while the observed increase in risk of EMT may be due to small-study bias.

Association of dental fluorosis with polymorphisms of estrogen receptor gene in Chinese children

Dental fluorosis (DF) is one of the important performances of endemic fluorosis. Some studies indicated that estrogen receptor (ESR) gene polymorphisms were associated with bone metabolism-related diseases. Therefore, it is possible that the variation in ESR genotypes will be associated with DF status. A case-control study was conducted among children aged 8-12 years with (n = 75) or without (n = 165) DF in China to investigate the relationship between ESR gene polymorphisms and DF. Gene polymorphisms were genotyped using the PCR-RFLP procedure. Children carrying R allele of ER RsaI had significantly increased risk of DF (Odds ratio (OR) = 1.821; 95% confidence interval (CI), 1.013-3.274) compared to children carrying r allele of ER RsaI in endemic fluorosis villages. For children with high-loaded fluoride status, carrying X allele of ESRα XbaI had a significantly decreased risk of DF (OR = 0.542; 95% CI, 0.314-0.936) compared to carrying x allele. This study provides the first evidence of an association between polymorphisms in the ESR gene with DF in high-fluoride-exposed populations. Further studies are needed to confirm the association.

Genetic variation in the sex hormone metabolic pathway and endometriosis risk: an evaluation of candidate genes

OBJECTIVE

To evaluate the relationship between common genetic variation in genes involved in the biosynthesis and signaling of estrogen and progesterone and endometriosis risk.

DESIGN

Genetic polymorphism analysis.

SETTING

Population-based case-control study conducted in Group Health Cooperative enrollees in western Washington.

PATIENT(S)

Women with newly diagnosed, surgically confirmed endometriosis between 1996 and 2001 (n = 256) and age- and reference year-matched female control subjects without a history of endometriosis (n = 567).

INTERVENTIONS(S)

None.

MAIN OUTCOME MEASURE(S)

We evaluated the relationship between common genetic variation and endometriosis risk, using gene-based tests and single-variant analysis of genetic polymorphisms in ESR1, ESR2, PGR, CYP17A1, CYP19A1, HSD17B1, HSD17B2, CYP1A1, CYP1A2, COMT, and GSTM1.

RESULT(S)

The most consistent gene-based association with endometriosis risk was for CYP19A1. We did not find evidence for consistent significant associations between previously reported candidate SNPs in sex hormone-related genes and endometriosis risk.

CONCLUSION(S)

In summary, we report increased endometriosis risk with CYP19A1 gene-based tests; replication of the association between endometriosis and this gene or gene region is necessary in a larger study population.

Polymorphisms in ESR1, ESR2 and HSD17B1 genes are associated with fertility status in endometriosis

OBJECTIVE

To investigate whether polymorphisms in genes involved in biosynthesis and signalling of sex steroids influence susceptibility to endometriosis and to infertility associated with it.

MATERIALS AND METHODS

Patients with endometriosis (n = 150) and fertile controls (n = 199) were genotyped for polymorphisms in oestrogen receptor genes ESR1 (rs2234693 - T/C single nucleotide polymorphism (SNP), dinucleotide (TA)(n) repeat) and ESR2 (dinucleotide (CA)(n) repeat), progesterone receptor gene PGR (rs10895068 - G/A SNP, 306-bp Alu-insertion), 17β-hydroxysteroid dehydrogenase type 1 gene HSD17B1 (rs605059 - A/G SNP), and aromatase gene CYP19A1 (rs10046 - C/T SNP, (TTTA)(n) tetranucleotide repeat, 3-bp TCT insertion/deletion polymorphism).

RESULTS

The HSD17B1 A/G SNP A allele increased overall endometriosis risk and the risk of stage I-II disease, while ESR1 longer (TA)(n) repeats only correlated with susceptibility to stage I-II endometriosis. When considering patients' fertility status, HSD17B1 A/G SNP A allele and ESR1 longer (TA)(n) repeats were associated with endometriosis accompanied by infertility, while ESR2 shorter (CA)(n) repeats were linked with endometriosis without infertility. Other polymorphisms were distributed similarly among patients and controls.

CONCLUSIONS

Genetic variants in ESR1, ESR2, and HSD17B1 genes could modify susceptibility to endometriosis and might influence the fertility status in endometriosis patients.

A review of estrogen receptor alpha gene (ESR1) polymorphisms, mood, and cognition

OBJECTIVE

There are significant individual differences in the extent to which mood and cognition change as a function of reproductive stage, menstrual phase, postpartum, and hormone therapy use. This review explores the extent to which variations or polymorphisms in the estrogen receptor alpha gene (ESR1) predict cognitive and mood outcomes.

METHODS

A literature search was conducted from 1995 to November 2009 through PubMed, Embase, and PsychINFO. Twenty-five manuscripts that summarize investigations of ESR1 in mental health were reviewed.

RESULTS

Among studies investigating ESR1 in relation to cognition, 11 of 14 case-control studies reported an association between ESR1 polymorphisms and risk for developing dementia. Three of four prospective cohort studies reported an association between ESR1 polymorphisms and significant cognitive decline. There are inconsistencies between case-control and cohort studies regarding whether specific ESR1 alleles increase or decrease the risk for cognitive dysfunction. The relationships between ESR1 and cognitive impairment tend to be specific to or driven by women and restricted to risk for Alzheimer disease rather than other dementia causes. Three of five studies examining ESR1 polymorphisms in relation to anxiety or depressive symptoms found significant associations. Significant associations have also been reported between ESR1 polymorphisms and childhood-onset mood disorder and premenstrual dysphoric disorder.

CONCLUSIONS

A strong relationship between ESR1 variants and cognitive outcomes is evident, and preliminary evidence suggests a role of the ESR1 gene in certain mood outcomes. Insights into the discordant results will come from future studies that include haplotype analyses, analyses within specific ethnic/racial populations, and sex-stratified analyses.

Racial and ethnic disparities in benign gynecologic conditions and associated surgeries

Common gynecologic conditions and surgeries may vary significantly by race or ethnicity. Uterine fibroid tumors are more prevalent in black women, and black women may have larger, more numerous fibroid tumors that cause worse symptoms and greater myomectomy complications. Some, but not all, studies have found a higher prevalence of endometriosis among Asian women. Race and ethnicity are also associated with hysterectomy rate, route, and complications. Overall, the current literature has significant deficits in the identification of racial and ethnic disparities in the incidence of fibroid tumors, endometriosis, and hysterectomy. Further research is needed to better define racial and ethnic differences in these conditions and to examine the complex mechanisms that may result in associated health disparities.