Functional genetic polymorphisms and female reproductive disorders: Part I: Polycystic ovary syndrome and ovarian response

Polymorphisms in FSHR modulating susceptibility to polycystic ovary syndrome: an updated meta-analysis

BACKGROUND

Two polymorphisms, rs6165 and rs6166 located in the intracellular domain of FSHR has been reported to affect folliculogenesis, steroidogenesis and oocyte maturation. Several studies have highlighted the role of FSHR polymorphisms in PCOS but the findings are conflicting. A meta-analysis was carried out to decipher the emerging perspectives.

METHODOLOGY

A comprehensive literature search was made using PubMed, PCOSkb, and Google Scholar. New Ottawa Scale has been utilized to evaluate the quality of each article. To evaluate the strength of association under different genetic models of rs6165 and rs6166 polymorphisms, odds ratio with a 95% confidence interval (CI) was calculated.

RESULTS

A total of 20 articles were selected for the present study. In pooled analysis and after the stratification by ethnicity, polymorphism rs6165 remains unrelated to the onset of PCOS. Besides, rs6166 exhibits significant protection in the Indian population under recessive, additive, and allele models (OR = 0.7, CI: 0.54-0.9, p = 0.006, OR = 0.65, CI: 0.48-0.89, p = 0.006, OR = 0.82, CI: 0.7-0.95, p = 0.01, respectively) and low to moderate risk in the Caucasian population under allele model (OR = 1.17, CI: 1.04-1.32, p = 0.01).

CONCLUSION

This meta-analysis suggests that GG genotype of rs6166 provides protection against PCOS, in a population-specific manner.

Gonadotropin receptor polymorphisms (FSHR N680S and LHCGR N312S) are not predictive of clinical outcome and live birth in assisted reproductive technology

OBJECTIVE

To study the consequences of specific genotype profiles of follicle-stimulating hormone receptor (FSHR) and luteinizing hormone choriogonadotropin receptor (LHCGR) on assisted reproductive technology outcomes when preimplantation genetic testing for aneuploidy is used for controlling the embryo ploidy status. The most common reported single-nucleotide polymorphisms in the amino acid position for the FSHR (N680S; N: asparagine, S: serine; [rs6166]) and the LHCGR (N312S variant; N: asparagine, S: serine [rs2293275]) were chosen for this study.

DESIGN

Retrospective cohort study.

SETTING

Private Fertility Clinic.

PATIENT(S)

All women aged 18-40 years undergoing their first assisted reproductive technology cycle with aneuploidy screening between 2006 and 2017 with body mass index of >18 and <40 kg/m² were included.

INTERVENTION(S)

All patients received both recombinant follicle-stimulating hormone and human menopausal gonadotropin or low dose human chorionic gonadotropin. Genomic DNA was isolated from patients' blood. Genotyping of the FSHR and LHCGR polymorphisms was performed using TaqMan genotyping assays. Associations between both receptor genotypes and clinical outcomes were assessed using generalized regression and ANOVA.

MAIN OUTCOMES MEASURE(S)

Live birth rate was the primary outcome. Secondary outcomes included oocyte yield, mature oocytes, blastulation rate, usable blastocyst rate, and implantation rate.

RESULT(S)

A total of 1,183 patients met the inclusion criteria and generated reliable genotype results. The overall genotype frequencies in the study population for the FSHR gene were as follows: 21.7% homozygous for S in codon 680, 29.2% homozygous for N680, and 48.1% heterozygous (N680S). As for the LHCGR, 15.6% were homozygous for N312, 38.5% homozygous for S312 and 45.9% heterozygous (N312S). Our study population consisted of 53.8% non-Hispanic white; 6.1% Hispanic white; 4.1% Afro-American; 15.4% Asian; and 20.6% other or unknown. No significant association was found with any of the studied variables (oocyte yield, usable blastocyst rate, implantation rate, live birth) when genotypes were analyzed per receptor or in combination with one another. There was a statistically significant but clinically irrelevant difference in the rate of mature oocytes across different variant combinations.

CONCLUSION(S)

Our findings suggest that the presence of gonadotropin receptor polymorphisms in both FSHR N680S and LHCGR N312S are not associated with assisted reproductive technology outcomes; therefore, these variants should not be considered reproductive predictors.

Follicular fluid lipidomic profiling reveals potential biomarkers of polycystic ovary syndrome: A pilot study

BACKGROUND

Polycystic ovary syndrome (PCOS) is a heterogeneous endocrine disorder associated with multiple metabolic conditions including obesity, insulin resistance, and dyslipidemia. PCOS is the most common cause of anovulatory infertility; however, the molecular diversity of the ovarian follicle microenvironment is not fully understood. This study aimed to investigate the follicular fluid (FF) lipidomic profiles in different phenotypes of PCOS and to explore novel lipid biomarkers.

METHODS

A total of 25 women with PCOS and 12 women without PCOS who underwent in vitro fertilization and embryo transfer were recruited, and their FF samples were collected for the lipidomic study. Liquid chromatography-tandem mass spectrometry was used to compare the differential abundance of FF lipids between patients with different PCOS phenotypes and controls. Subsequently, correlations between specific lipid concentrations in FF and high-quality embryo rate (HQER) were analyzed to further evaluate the potential interferences of lipid levels with oocyte quality in PCOS. Candidate biomarkers were then compared via receiver operating characteristic (ROC) curve analysis.

RESULTS

In total, 19 lipids were identified in ovarian FF. Of these, the concentrations of ceramide (Cer) and free fatty acids (FFA) in FF were significantly increased, whereas those of lysophosphatidylglycerol (LPG) were reduced in women with PCOS compared to controls, especially in obese and insulin-resistant groups. In addition, six subclasses of ceramide, FFA, and LPG were correlated with oocyte quality. Twenty-three lipid subclasses were identified as potential biomarkers of PCOS, and ROC analysis indicated the prognostic value of Cer,36:1;2, FFA C14:1, and LPG,18:0 on HQER in patients with PCOS.

CONCLUSIONS

Our study showed the unique lipidomic profiles in FF from women with PCOS. Moreover, it provided metabolic signatures as well as candidate biomarkers that help to better understand the pathogenesis of PCOS.

An investigation of steroid biosynthesis pathway genes in women with polycystic ovary syndrome

Background:

Polycystic ovary syndrome (PCOS) is a common endocrinopathy whose heterogeneous genetic basis results in a variable clinical presentation. One of the main clinical features of PCOS is hyperandrogenism which occurs due to dysregulation of ovarian and adrenal steroidogenesis.

Aims:

This study aimed to investigate potentially pathogenic variants in steroidogenic genes associated with PCOS.

Settings and Design:

This was a hospital-based observational study.

Materials and Methods:

We recruited 51 women who presented with PCOS. Fasting blood samples were drawn from the participants and their whole-exome sequencing analysis was carried out to look for pathogenic variants involved in steroidogenic pathways. The variants were predicted for their probable deleterious effects on proteins through in silico prediction tools. We evaluated the variants with respect to the hormonal characteristics and clinical outcomes of the patients.

Statistical Analysis Used:

All variables were analysed using GraphPad Prism 8. Kruskal–Wallis t-test and Fisher's exact test were used to compare clinical parameters and frequency differences among PCOS patients with and without variants.

Results:

The data presented here reveal eight heterozygous exonic variants, namely CYP21A2 (p.Ala392Thr, p.Gln319Ter and p.I143N), steroidogenic acute regulatory (p.Arg53 Leu), AKR1C3 (p.Phe205Val), P450 oxidoreductase (p.Val334Ile and p.Val251Met) and HSD17B6 (p.Gly40Ser), of which three were pathogenic, and four variants of uncertain significance in 8 out of 51 patients (15.68%). The identified variants were predicted to cause protein destabilisation, thus likely contributing to the pathogenesis of PCOS. Some of the variants showed significant differences between PCOS patients and population database (P < 0.05).

Conclusion:

The results of this study add to the mutational spectrum of steroidogenic genes and their association with PCOS.

The Role of FSHR SNPs and AMH in Follicular Fluid and Serum in Ovarian Response during COS: A Pilot Study

Background

Several studies have investigated on the polymorphism Ser680Asn of FSHR and its use as a predictive indicator of response to an IVF/ICSI protocol. Furthermore, measurement of AMH in serum and follicular fluid is a useful prognostic indicator for the outcome of an assisted reproduction attempt. The purpose of this study is to examine the FSH receptor Ser680Asn polymorphism in combination with AMH levels in both serum and follicular fluid, on the day of oocyte collection.

Materials and Methods

A total of 32 women who underwent IVF/ICSI were included. Women were grouped into 2 groups: those who received rFSH (n = 11) and those who received hMG (n = 21). Serum AMH was measured on day 3 of the cycle, and AMH in the follicular fluid on the day of oocyte retrieval; the same day peripheral blood was collected for the genotyping of Ser680Asn.

Results

No statistical significant difference was found between serum AMH and follicular fluid AMH regarding the FSH receptor genotype for the Ser680Asn polymorphism. Regarding the sAMH/ffAMH ratio in the 3 genotypes, the value was lower in Asn/Asn women than Ser/Ser and Ser/Asn, but no statistical difference was obtained. Women who carry the Ser allele have a higher number of follicles, retrieved oocytes, and mature oocytes than women who do not contain the Ser allele. Women with AMH < 2.22 ng/ml presented lower AMH follicular fluid levels and lower serum AMH/follicular fluid AMH ratio in a statistically significant manner. Concerning the genotype for the polymorphism Ser680Asn of FSHR in relation to AMH levels, no statistically significant differences were found.

Conclusions

The identification of polymorphisms, such as Ser680Asn of FSHR, along with the determination of endocrine markers in the follicular fluid, such as AMH, could lead at some point, to the personalized therapy setting per woman.

Investigation of the FSHR, CYP11, and INSR Mutations and Polymorphisms in Iranian Infertile Women with Polycystic Ovary Syndrome (PCOS)

Background

Polycystic ovary syndrome (PCOS) is the most common cause of ovarian dysfunction associated with infertility, Oligomenorrhea or amenorrhea, hirsutism, acne, and obesity. A large body of evidence unraveled, three major groups of genes play critical roles in underlying PCOS molecular mechanism. The aim of this study is to investigate critical exonic variant of FSHR, CYP11, and INSR and determine the functionality of these mutations in Iranian patients with PCOS.

Methods

In this case-control study, 130 patients with PCOS who referred to the Vali-e-Asr Hospital with infertility were included. DNA extracted from three ml of peripheral blood of the participants for DNA extraction. The PCR was conducted for each gene and the PCR product was genotyped by sequencing.

Results

The data showed that there were two polymorphisms in INSR genes which did not change the protein sequences; these alterations can also be considered as a single nucleotide polymorphism (SNP). Moreover, any exonic variant has not been detected in CYP11B1. Whereas, two missense mutation have been detected in FSHR gene including p.Ala307Thr and p.Asn680Ser. It has been shown that the polymorphisms of the FSHR gene affect the hormone response in the ovaries. Our data demonstrated that the FSHR mutations frequencies were higher in the patients with PCOS rather than control people significantly.

Conclusion

These data showed that the polymorphisms of FSHR were significantly associated with PCOS in Iranian infertile women. Further studies with larger sample sizes are needed to be performed for explore the strength of the association.

GDF9 polymorphisms: influence on ovarian response in women undergoing controlled ovarian hyperstimulation

OBJECTIVE

The study looked into the possible influence of GDF9 polymorphisms on ovarian response in women with a normal ovarian reserve undergoing controlled ovarian hyperstimulation for in vitro fertilization (IVF).

METHODS

This cross-sectional study included 67 women with normal ovarian reserve aged 30-39 years submitted to controlled ovarian hyperstimulation for IVF. We sequenced four polymorphisms in the GDF9 gene (C398G, C447T, G546A, and G646A) and analyzed their influence on follicular and oocyte outcomes.

RESULTS

The mutant allele C398G decreased the total number of follicles >17mm (6.49 vs. 4.33, p=0.001), total number of follicles (10.11 vs. 7.33, p=0.032), number of MII oocytes retrieved, and serum progesterone levels on trigger day. The C447T polymorphism was associated with a greater number of follicles between 12 and 14 mm on the day of r-hCG, while the G546A polymorphism was associated with lower serum progesterone levels on trigger day.

CONCLUSIONS

GDF9 gene polymorphisms C398G and C447T adversely affected ovarian response in women undergoing controlled ovarian hyperstimulation. These findings show that in addition to playing a role in the early stages of folliculogenesis, GDF9 polymorphisms have an important impact on the final stage of oocyte development.

CYP19A1 Gene Expression in Patients with Polycystic Ovarian Syndrome

Context:

Polycystic ovarian syndrome (PCOS) is a common endocrine system disorder among the women of reproductive age, yet the etiology of PCOS remains unclear. Infertility in females with PCOS can be caused by anovulation, high luteinizing hormone levels, and hyperandrogenism.

Aims:

This research analyzed the role of the aromatase gene (CYP19A1) in PCOS pathogenesis.

Settings and Design:

This study used an observational, cross-sectional design.

Subjects and Methods:

A total of 110 research participants (55 PCOS patients and 55 non-PCOS patients) were included in the study.

Statistical Analysis Used:

A real-time quantitative polymerase chain reaction was used to analyze the mRNA expression for aromatase in granulosa cells.

Results:

The relative expression of aromatase mRNA is lower in women with PCOS compared to those without PCOS (P < 0.05). Relative expression of CYP19A1 (aromatase) mRNA in PCOS group was 0.38 ± 0.25, whereas in non-PCOS group was 1.00 ± 0.00. The decline in aromatase activity contributes to an increase in testosterone level. This condition has a role in hyperandrogenism which is a typical characteristic of PCOS women. Granulosa cells in polycystic ovary undergo disturbance in the development and cannot respond to follicle-stimulating hormone (FSH) stimulation. Lack of stimulation of FSH causes induction inadequacy to aromatase enzyme activity in the aromatization process. The decline in FSH activity is caused by various factors that are associated with typical characteristics of PCOS.

Conclusions:

There is a decrease in the relative expression rate of granulosa cells’ aromatase mRNA in women with PCOS compared to the non-PCOS.

Pharmacogenetics of FSH Action in the Female

The purpose of a pharmacogenomic approach is to tailor treatment on the basis of an individual human genotype. This strategy is becoming increasingly common in medicine, and important results have been obtained in oncologic and antimicrobial therapies. The rapid technological developments and availability of innovative methodologies have revealed the existence of numerous genotypes that can influence the action of medications and give rise to the idea that a true "individualized" approach could become in the future a reality in clinical practice. Moreover, compared to the past, genotype analyses are now more easily available at accessible cost. Concerning human reproduction, there is ample evidence that several variants of gonadotropins and their receptors influence female reproductive health and ovarian response to exogenous gonadotropins. In more detail, variants in genes of follicle-stimulating hormone β-chain (FSH-B) and its receptor (FSH-R) seem to be the most promising candidates for a pharmacogenomic approach to controlled ovarian stimulation in assisted reproductive technologies. In the present review, we summarize the evidence regarding FSH-B and FSH-R variants, with special reference to their impact on reproductive health and assisted reproductive technology treatments.

Follicle Stimulating Hormone Receptor (FSHR) Polymorphisms and Polycystic Ovary Syndrome (PCOS)

Polycystic ovary syndrome (PCOS) is the commonest endocrine abnormality in women of reproductive age typically presenting with chronic oligo- or anovulation, clinical, or biochemical hyperandrogenism and polycystic ovarian morphology (PCOM). Restoring mono-ovulation is the ultimate goal of ovulation induction and most women do respond to ovulation inducing agents causing their Follicle-stimulating hormone (FSH) levels to rise. Familial clustering and the results from twin studies strongly support an underlying genetic basis for PCOS. Recent Genome wide association studies (GWAS) have identified several genetic variants being genome wide significantly associated with PCOS. Amongst those are variants in or near the Luteinizing hormone (LH) and FSH receptor genes as well as a variant in the FSH-β gene. The aim of this review is to summarize the available evidence as to whether single nucleotide polymorphisms are able to modify the PCOS phenotype or whether they constitute a risk factor for the syndrome. Data on the role of FSHR polymorphisms in PCOS are conflicting. It seems that in large Chinese studies FSHR polymorphisms are not associated with either PCOS risk or with PCOS treatment outcome. However, in large scale studies in Caucasians these polymorphisms seem to influence the risk of having PCOS. Moreover, these studies also showed that some polymorphisms might affect some clinical features of PCOS as well as treatment outcome. Although most research has focussed on the role of FSHR polymorphisms there seems to be also some evidence showing that single nucleotide polymorphisms (SNPs) in the LHCG-Receptor as well as those in FSH-β gene might also alter the phenotype of PCOS. In conclusion most studies confirm that FSHR polymorphisms do alter the phenotype of PCOS in that they either alter the response to exogenous FSH or hat they increase the risk of having PCOS.

Frequency of the T307A, N680S, and -29G>A single-nucleotide polymorphisms in the follicle-stimulating hormone receptor in Mexican subjects of Hispanic ancestry

BACKGROUND

FSHR SNPs may influence the ovarian sensitivity to endogenous and exogenous FSH stimulation. Given the paucity of data on the FSHR c.919A > G, c.2039A > G and - 29G > A SNPs in Hispanic population, we here analyzed their frequency distribution in Mexican mestizo women.

METHODS

Samples from 224 Mexican mestizo women enrolled in an IVF program as well as a genotype database from 8182 Mexican mestizo subjects, were analyzed for FSHR SNPs at positions c.919, c.2039 and - 29G > A. Association between the genetic variants and reproductive outcomes was assessed.

RESULTS

The c.919 and c.2039 SNPs were in strong linkage disequilibrium and their corresponding genotype frequencies in the IVF group were: AA 46.8%, AG 44.2%, and GG 8.9%, and AA 41.9%, AG 48.2% and GG 9.8%, respectively. For the -29G > A SNP, genotype frequencies were 27% (GG), 50% (GA) and 23% (AA). In normal oocyte donors with the c.2039 GG genotype, the number of oocytes recovered after ovarian stimulation (COS) were significantly (p < 0.01) lower than in those bearing other genotypes in this or the -29G > A SNP. Analysis of the large scale database revealed that both allelic and genotype frequencies for the three SNPs were very similar to those detected in the IVF cohort (p ≥ 0.38) and that female carriers of the c.2039 G allele tended to present lower number of pregnancies than women bearing the AA genotype; this trend was stronger when women with more Native American ancestry was separately analyzed (OR = 2.0, C.I. 95% 1.03-3.90, p = 0.04). There were no differences or trends in the number of pregnancies among the different genotypes of the -29G > A SNP.

CONCLUSIONS

The frequency of the GG/GG combination genotype for the c.919 and c.2039 SNPs in Mexican hispanics is among the lowest reported. The GG genotype is associated with decreased number of oocytes recovered in response to COS as well as to lower pregnancy rates in Hispanic women from the general population. The absence of any effect of the -29AA genotype on the response to COS, indicates that there is no need to perform this particular genotype testing in Hispanic women with the purpose of providing an individually-tailored COS protocol.

The impact of FSH receptor polymorphism on time-to-pregnancy: a cross-sectional single-centre study

Background

Single nucleotide polymorphism of the follicle-stimulating hormone (FSH) receptor (FSHR) is an important marker of ovarian function. However, its role in female fecundity remains debatable. The aim of the study to assess the relationship of FSHR polymorphism of Serine/Serine, Asparagine/Asparagine and Asparagine/Serine variants directly against the time-to-pregnancy (TTP) in women.

Methods

Data were collected from 291 consecutive selected post-partum Caucasians using this criterion: ethnicity, age between 21 and 34-year-old new mothers and, 0–3 days after delivery of newborns in the Klaipeda University Hospital, Lithuania. Questionnaires on factors associated with conception were given to patients, and blood samples were collected for genomic DNA extractions as well as for analysis of follicle-stimulating hormone receptor gene polymorphism. Odds ratios (OR) and 95% confidence intervals (CI) for time-to-pregnancy were estimated by multivariate logistic regression. Women with unplanned pregnancies and those who received assisted reproductive technologies were not included in the study.

Results

After adjustment for other possible factors, increased risk for time-to-pregnancy of 12 or more months was associated with: Serine/Serine polymorphism variant (OR = 1.38, 95% CI 1.56–2.71, p = 0.007), age of 30 or more years (OR = 1.95, 95% CI 1.25–2.71, p = 0.015), gynaecological diseases in the past (OR = 2.21, 95% CI 1.12–5.74, p = 0.027), prior contraception use (OR = 1.87, 95% CI 1.14–3.64, p = 0.016), and fertility problems in the past (OR = 1.57, 95% CI 1.16–4.76, p = 0.019).

Conclusion

The results suggest a possible relationship of FSH receptor gene Serine/Serine variant for the lower possibility of conception during the first 12 months of planned conception.

Pharmacogenetic algorithm for individualized controlled ovarian stimulation in assisted reproductive technology cycles

Controlled ovarian stimulation (COS) is crucial for optimizing in-vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) success. Multiple factors influence the ovarian response to COS, making predictions about oocyte yields not so straightforward. As a result, the ovarian response may be poor or suboptimal, or even excessive, all of which have negative consequences for the affected patient. There is a group of patients that present with a suboptimal response to COS despite normal biomarkers of ovarian reserve, such as AFC and AMH. These patients have a lower number of retrieved oocytes than what was expected based on their ovarian reserve, thus showing the inadequacy of using only the traditional ovarian reserve biomarkers to predict the ovarian response. Suboptimal response to COS might be related to ovarian sensitivity to exogenous gonadotropins modulated by genetic factors. The understanding of the gene polymorphisms related to reproductive function can help to improve the clinical management of this patient population and to explain some of the individual patient variability in response to COS. The development of a pharmacogenetic approach concerning COS in the context of assisted reproduction seems attractive as it might help to understand the relationship between genetic variants and ovarian response to exogenous gonadotropins. The patient's genetic profile could be used to select the most appropriate gonadotropin type, predict the optimal dosage for each drug, develop a cost-effective treatment plan, maximize the success rates, and lastly, decrease the time-to-pregnancy.

Polycystic ovary syndrome: definition, aetiology, diagnosis and treatment

Polycystic ovary syndrome (PCOS) is one of the most common endocrine and metabolic disorders in premenopausal women. Heterogeneous by nature, PCOS is defined by a combination of signs and symptoms of androgen excess and ovarian dysfunction in the absence of other specific diagnoses. The aetiology of this syndrome remains largely unknown, but mounting evidence suggests that PCOS might be a complex multigenic disorder with strong epigenetic and environmental influences, including diet and lifestyle factors. PCOS is frequently associated with abdominal adiposity, insulin resistance, obesity, metabolic disorders and cardiovascular risk factors. The diagnosis and treatment of PCOS are not complicated, requiring only the judicious application of a few well-standardized diagnostic methods and appropriate therapeutic approaches addressing hyperandrogenism, the consequences of ovarian dysfunction and the associated metabolic disorders. This article aims to provide a balanced review of the latest advances and current limitations in our knowledge about PCOS while also providing a few clear and simple principles, based on current evidence-based clinical guidelines, for the proper diagnosis and long-term clinical management of women with PCOS.

The Impact of FSHR Gene Polymorphisms Ala307Thr and Asn680Ser in the Endometriosis Development

Endometriosis is an estrogen-dependent inflammatory disease that affects a large number of women in reproductive age. Follicle-stimulating hormone (FSH) plays a role in steroidogenesis and acts through a transmembrane glycoprotein, FSH receptor (FSHR). Polymorphisms in FSHR gene were previously associated with variability in FSH serum level and reproductive outcomes, but its relation with endometriosis has not been clarified and demonstrated conflicting results, ranging from strong links to no association to endometriosis. Inspired by these findings, we aimed to investigate the influence of FSHR Ala307Thr and Asn680Ser polymorphisms in the risk of endometriosis development and/or progression and the status of fertility in 352 women with endometriosis and 510 fertile controls. Single-marker analysis revealed no significant difference for both Ala307Thr and Asn680Ser polymorphisms between overall endometriosis and control group. However, when the endometriosis group was subdivided according to fertility status and disease stage, a positive association was found between 680Ser/Ser or GG genotype of the Asn680Ser polymorphism and fertile women with endometriosis (p = 0.004). Combined alleles of FSHR polymorphisms revealed that "GG/307Ala680Ser" was more frequently found in fertile women with endometriosis (haplotype frequency of 45.4% in fertile women with endometriosis and 38.3% in controls, p = 0.041). The combined alleles of FSHR polymorphisms disclosed that "GG/307Ala680Ser" was more frequently found in fertile women with endometriosis (haplotype frequency of 45.4% in fertile women with endometriosis and 38.3% in controls, p = 0.049), while "GA/307Ala680Asn" haplotype was less frequently found in endometriosis group (haplotype frequency of 6.5% in cases and 11.9% in controls, p = < 0.001), regardless of fertility status and stage of the disease. The findings suggest that 680Ser-Ser/GG genotype and "GG/307Ala680Ser" haplotype increase the risk of endometriosis in fertile women, while "GA/307Ala680Asn" haplotype decreases the risk of endometriosis development and progression.

Characterization of polymorphism in the FSH receptor gene and its impact on some reproductive indices in dairy cows

Follicle stimulating hormone (FSH) is released from the anterior pituitary gland and has an important role in female fertility. As FSH is a glycoprotein polypeptide hormone which cannot pass through the cell membrane, its influence on target cells must be mediated by the FSH receptor (FSHR). Accordingly, any kind of mutation in FSHR can affect reproduction in dairy cows. In this study, the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique was used for recognition of a point mutation (A/G: position -278) located in the FSHR gene in Iranian dairy cows. The association was evaluated of this mutation with reproductive performance. Blood samples were collected from 79 cows in a dairy farm in Iran and genotyped based on this single nucleotide polymorphism (SNP). The 5'-flanking regions of FSHR gene were successfully amplified and produced a fragment of 211bp in all cases. Three different patterns were, however, produced following restriction digestion with FaqI enzyme. The molecular results showed the existence of three different genotypes of AA, AG and GG among examined cows. In this study percentages of genotypes were 51.9%, 43.2% and 4.9% for AA, AG and GG genotypes, respectively. Allele frequencies were 73.5% and 26.5% for A and G, respectively. Results indicate that cows lacking allele G had desirable fertility in which a greater percentage (53.7%) of cows lacking Allele G (AA) had services per conception (SPC) of <2 in the previous lactation; while a lesser percentage of cows with Allele G (28.9%) had SPC of <2 (P<0.05). There was no difference in the days non-pregnant (DNP) and calving to first service interval among cows with these genotypes (P>0.05). Calving to first service interval was 69.9 ±12.3 in cows with Allele G and 74.73±13.9 in cows without Allele G (P>0.05). Percentage of cows with repeat breeder syndrome (SPC >3) was also 15.6% and 27.6% in cows without Allele G and with Allele G, respectively, but these values were not different (P>0.05). It can be concluded that the A to G mutation within the upstream region of FSHR gene (position -278) may affect some reproductive variables in Holstein dairy cows.

Use of Bone Morphogenetic Protein 15 Polymorphisms to Predict Ovarian Stimulation Outcomes in Infertile Brazilian Women

AIMS

Polymorphisms in the gene encoding bone morphogenetic protein 15 (BMP15) can result in inhibited secretion or lowered bioactivity of the BMP15 protein. BMP15 levels are associated with follicle-stimulating hormone receptor (FSHR) action on granulosa cells, wherein FSHR increases the sensitivity of ovarian follicles to follicle-stimulating hormone (FSH). In this study we evaluated the BMP15 polymorphisms A905 > G/rs3897937, C901 > T/rs17003221, and C-9 > G/rs3810682 in infertile Brazilian women in terms of anti-Mullerian hormone (AMH), FSH, and estradiol serum levels, as well as controlled ovarian hyperstimulation response and assisted reproduction outcomes.

METHODS

A cross-sectional study comprising 186 infertile women who underwent the first cycle of high complexity assisted reproduction treatment was conducted using the TaqMan assay for quantitative polymerase chain reaction genotyping. Serum AMH, FSH, and estradiol levels were measured by enzyme-linked immunosorbent assay.

RESULTS

For C901 > T (rs17003221) carriers, there was a statistically significant difference among carriers of a polymorphic BMP15 genotype (TT) and the estradiol concentration. These women had higher estradiol levels than women who had homozygous wild type or heterozygous genotypes. There was also a positive correlation between serum AMH and the C-9 > G (rs3810682) polymorphism, wherein women carrying both polymorphic alleles (homozygous, GG) had higher average AMH levels than heterozygous women. However, none of the three polymorphisms studied showed a statistically significant correlation with assisted reproduction outcome.

DISCUSSION

Oocytes are known to secrete factors that regulate follicular development and oocyte maturation. Abnormal expression of these factors may thus be involved in follicular development disorders. A recent study highlighted the importance of BMP15 in regulating ovulation rates in sheep and that heterozygous deletions in the -9C > G polymorphism reduced BMP15 concentrations, increased granulosa cell FHSR mRNA levels, elevated estrogen secretion, and activated production of stem cell factors. In this study we found that BMP15 polymorphisms affected estrogen and AMH levels.

CONCLUSION

BMP15 polymorphisms are not correlated with ovarian stimulation and assisted reproduction outcomes in infertile Brazilian women.

Clinical efficacy of recombinant versus highly purified follicle-stimulating hormone according to follicle-stimulating hormone receptor genotype

OBJECTIVE

Conflicting data have been reported on the comparative doses of recombinant follicle-stimulating hormone (rFSH) and urinary highly purified follicle-stimulating hormone (HP-FSH) required for ovarian stimulation. Nothing is known about the clinical efficacy of rFSH or HP-FSH depending on the N680S follicle-stimulating hormone receptor (FSHR) polymorphism. Our aim was to investigate whether the N680S polymorphism of the FSHR gene affects ovarian response with different forms of FSH.

MATERIALS AND METHODS

This retrospective cohort study includes 382 cycles performed at Instituto Bernabeu from 191 oocyte donors. All donors carried out two cycles: one with rFSH and the other one with HP-FSH (group 1, n=63), both with HP-FSH (group 2, n=100) or both with rFSH (group 3, n=28). The results were compared by pairs from each patient. The main outcomes were oocyte yield, metaphase II matured oocytes (MII), days of stimulation, and gonadotropin dosage.

RESULTS

No significant differences were found when we compared the cycles for donors in group 1. However, according to the FSHR polymorphism, statistical differences were shown. For the SS genotype, more oocytes (16.9 vs. 18.4) and MII (12.8 vs. 15.5) were yielded in the HP-FSH cycle. For the NS genotype, more oocyte (20.1 vs. 16.9) and MII (17.4 vs. 14.2) were yielded in the rFSH cycle. For the NN genotype, no differences were found. No differences were found when we compared the cycles in groups 2 and 3 irrespective of the FSHR polymorphism.

CONCLUSION

For the first time, we have shown in a population of egg donors that the N680S FSHR gene polymorphism affects the efficacy of HP-FSH or rFSH. The FSHR genotype is an important factor to determine the dosage and the nature of the gonadotropin selected for ovarian stimulation.

Mutation analysis of exon1 of bone morphogenetic protein-15 gene in Iranian patients with polycystic ovarian syndrome

BACKGROUND

With the prevalence of 6-10%, polycystic ovarian syndrome (PCOS) is considered the most common endocrinological disorder affecting women in their reproductive age. It has been suggested that genetic factors participate in the development of PCOS. Follicular development has been considered as one of the impaired processes in PCOS. Bone morphogenetic protein-15 (BMP-15) gene is a candidate gene in follicular development and its variants may play role in pathogenesis of PCOS.

OBJECTIVE

To investigate whether BMP-15 gene mutations are present in Iranian women with PCOS.

MATERIALS AND METHODS

In this cross-sectional study 5 ml venous blood samples was taken from 70 PCOS women referring to Afzalipour Hospital, Kerman University of Medical Sciences, Kerman, Iran, between January to December 2014. Genomic DNA was extracted from the blood sample by salting out method. Then a set of PCR reactions for exon1 of BMP-15 gene was performed using specific primers followed by genotyping with direct sequencing.

RESULTS

Two different polymorphisms were found in the gene under study. In total 20 patients (28.6%) were heterozygote (C/G), and 2 patients (2.86%) were homozygous (G/G) for c.-9C>G in 5´UTR promoter region of BMP-15 gene (rs3810682). In addition, in the coding region of exon1, three patients (4.3%) were heterozygote (G/A) for c.A308G (rs41308602). Two PCOS patients (2.86%) appeared to have both c.-9C>G (C/G) and c.A308G (G/A) variants simultaneously.

CONCLUSION

Our research detected two polymorphisms of BMP-15 gene among PCOS patients, indicating that even though it cannot be concluded that variants of BMP-15 gene are the principal cause of polycystic ovarian syndrome; they could be involved in pathogenic process in development of PCOS.

Identification of genetic variants in TNF receptor 2 which are associated with the development of cervical carcinoma

Cervical cancer is one of the most common malignancies among women in India. Beside HPV, other factors present in host also put their role in the progression of cervical tumerogenesis. In present study, we screened 300 subjects to identify variations in TNFR2 gene by PCR-dHPLC method followed by direct sequencing. We identified six known and four novel variations in six different exons of TNFR2 gene. Out of these identified variations, five known variations were found to be significantly associated with the risk of cervical cancer (p < 0.0001). On construction of haplotypes, one haplotype (TTGCC) was emerged as a major protective type while two (CAAGC + CTGCC) were revealed as major risk haplotypes. In conclusion, postmenopausal women having CAAGC + CTGCC haplotypes in TNFR2 gene along with HPV infection and tobacco consumption may lead to the development of cervical cancer.

Effect of follicle-stimulating hormone receptor Asn680Ser polymorphism on the outcomes of controlled ovarian hyperstimulation: an updated meta-analysis of 16 cohort studies

PURPOSE

The purpose of this study is to evaluate the influence of follicle-stimulating hormone receptor (FSHR) Asn680Ser polymorphism on the ovarian response to exogenous follicle-stimulating hormone (FSH) and clinical outcomes in women undergoing controlled ovarian hyperstimulation (COH).

METHODS

A database search was conducted to identify the eligible studies that investigated the effect of FSHR Asn680Ser polymorphism on ovarian response and clinical outcomes. A pooled analysis was performed with the odds ratio (OR) or weighted mean difference (WMD) and their respective 95 % confidence interval (CI) by the STATA software with random effects model.

RESULTS

Sixteen cohort studies comprising a total of 4287 subjects were included. The number of retrieved oocytes was significantly fewer in subjects with the SS genotype at position 680, compared to subjects with the NN or NS genotype (WMD = -1.36, 95 % CI = -1.85 to -0.87). Lack of association was detected between the genotypes (SS genotype vs. NN or NS genotype) and clinical outcomes such as exogenous FSH dose (WMD = 98.96 IU, 95 % CI = -22.33 to 220.24), poor response (OR = 1.08, 95 % CI = 0.71-1.64), ovarian hyperstimulation syndrome (OHSS) (OR = 1.58, 95 % CI = 0.41-6.07), and clinical pregnancy rate (OR = 1.10, 95 % CI = 0.86-1.40). However, poor ovarian response and number of retrieved oocytes were significantly influenced by the Asn680Ser polymorphism in the Asian subjects. In addition, no publication bias was detected.

CONCLUSION

FSHR Asn680Ser polymorphism might be a significant biomarker for predicting the number of retrieved oocytes and poor response, especially in Asian subjects. Other outcomes such as exogenous FSH dose, OHSS, and pregnancy rate were not influenced by FSHR Asn680Ser polymorphism.

Scientific Statement on the Diagnostic Criteria, Epidemiology, Pathophysiology, and Molecular Genetics of Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a heterogeneous and complex disorder that has both adverse reproductive and metabolic implications for affected women. However, there is generally poor understanding of its etiology. Varying expert-based diagnostic criteria utilize some combination of oligo-ovulation, hyperandrogenism, and the presence of polycystic ovaries. Criteria that require hyperandrogenism tend to identify a more severe reproductive and metabolic phenotype. The phenotype can vary by race and ethnicity, is difficult to define in the perimenarchal and perimenopausal period, and is exacerbated by obesity. The pathophysiology involves abnormal gonadotropin secretion from a reduced hypothalamic feedback response to circulating sex steroids, altered ovarian morphology and functional changes, and disordered insulin action in a variety of target tissues. PCOS clusters in families and both female and male relatives can show stigmata of the syndrome, including metabolic abnormalities. Genome-wide association studies have identified a number of candidate regions, although their role in contributing to PCOS is still largely unknown.

Comprehensive assessment of expression of insulin signaling pathway components in subcutaneous adipose tissue of women with and without polycystic ovary syndrome

Objective

Insulin resistance is a common feature of polycystic ovary syndrome (PCOS). The insulin signaling pathway consists of two major pathways, the metabolic and the mitogenic cascades. The many components of these pathways have not been comprehensively analyzed for differential expression in insulin-responsive tissues in PCOS. The goal of this study was to determine whether the core elements of the insulin signal transduction cascade were differentially expressed in subcutaneous adipose tissue (SAT) between PCOS and controls.

Materials/methods

Quantitative real-time PCR for 36 insulin signaling pathway genes was performed in subcutaneous adipose tissue from 22 white PCOS and 13 healthy controls.

Results

Genes in the insulin signaling pathway were not differentially expressed in subcutaneous adipose tissue between PCOS and controls (P > 0.05 for all). Components mainly of the mitogenic pathway were correlated with both androgens and metabolic phenotypes. Expression levels of five genes (MKNK1, HRAS, NRAS, KRAS, and GSK3A) were positively correlated with total testosterone level (ρ > 0, P < 0.05). Inverse correlation was found between expression of six genes (HRAS, MAP2K2, NRAS, MAPK3, GRB2, and SHC1) and metabolic traits (body mass index, fasting glucose, fasting insulin, and HOMA-IR) (ρ < 0, P < 0.05).

Conclusions

Differential expression of core insulin signaling pathway components in subcutaneous adipose tissue is not a major contributor to the pathogenesis of PCOS. Correlation between clinical phenotypes and expression of several genes in the mitogenic limb of the insulin signaling pathway suggests mitogenic signaling by insulin may regulate steroidogenesis and glucose homeostasis.

•

We examined gene expression in adipose tissue between PCOS and controls.

•

Complete coverage of core elements of the insulin signaling pathway.

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Differential mRNA expression in adipose tissue is not a major contributor to PCOS.

•

We discovered associations between mitogenic signaling components and phenotypes.

Pathway Analysis Based on a Genome-Wide Association Study of Polycystic Ovary Syndrome

Background

Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders in women of reproductive age, and it is affected by both environmental and genetic factors. Although the genetic component of PCOS is evident, studies aiming to identify susceptibility genes have shown controversial results. This study conducted a pathway-based analysis using a dataset obtained through a genome-wide association study (GWAS) to elucidate the biological pathways that contribute to PCOS susceptibility and the associated genes.

Methods

We used GWAS data on 636,797 autosomal single nucleotide polymorphisms (SNPs) from 1,221 individuals (432 PCOS patients and 789 controls) for analysis. A pathway analysis was conducted using meta-analysis gene-set enrichment of variant associations (MAGENTA). Top-ranking pathways or gene sets associated with PCOS were identified, and significant genes within the pathways were analyzed.

Results

The pathway analysis of the GWAS dataset identified significant pathways related to oocyte meiosis and the regulation of insulin secretion by acetylcholine and free fatty acids (all nominal gene-set enrichment analysis (GSEA) P-values < 0.05). In addition, INS, GNAQ, STXBP1, PLCB3, PLCB2, SMC3 and PLCZ1 were significant genes observed within the biological pathways (all gene P-values < 0.05).

Conclusions

By applying MAGENTA pathway analysis to PCOS GWAS data, we identified significant pathways and candidate genes involved in PCOS. Our findings may provide new leads for understanding the mechanisms underlying the development of PCOS.

Association between two polymorphisms of follicle stimulating hormone receptor gene and susceptibility to polycystic ovary syndrome: a meta-analysis

OBJECTIVE

To investigate the association between two polymorphisms of follicle stimulating hormone receptor (FSHR) gene and polycystic ovary syndrome (PCOS) susceptibility.

METHODS

Case-control studies on relationship of Thr307Ala and Asn680Ser polymorphisms in FSHR gene and PCOS susceptibility were searched from PubMed, ISI web of knowledge, EBSCO, and China National Knowledge Infrastructure (CNKI) databases up to March 21, 2013. The pooled odds ratio (OR) and 95% confidence interval (CI) were calculated using fixed- or random-effect model based on heterogeneity test in 5 genotype models analyses.

RESULTS

A total of 11 studies were included in the Meta-analysis. The random-effect analysis showed Asn680Ser was significantly associated with the reduced susceptibility to PCOS with dominant model (Asn/Asn+Asn/Ser vs. Ser/Ser, OR=0.83, 95% CI: 0.69-1.00), recessive model (Asn/Asn vs. Asn/Ser+ Ser/Ser, OR=0.84, 95% CI: 0.72-0.98), homozygote comparison (Asn/Asn vs. Ser/Ser, OR=0.79, 95% CI: 0.63-0.98), and the allele contrast (Asn vs. Ser, OR=0.87, 95% CI: 0.79-0.97) respectively(P=0.02, I(2)=56.0%), being protective factors for PCOS. However, no significant associations were found between Thr307Ala and PCOS.

CONCLUSION

There might be a significant association between Asn680Ser polymorphism and PCOS.

The Ser680Asn polymorphism in the follicle-stimulating hormone receptor gene is associated with the ovarian response in controlled ovarian hyperstimulation

OBJECTIVE

Polymorphisms in the follicle-stimulating hormone receptor (FSHR) gene are reported to be associated with the ovarian response in controlled ovarian hyperstimulation (COH), although there remains some discordance between studies. Here, using the largest patient sample to date, we evaluated the association of the p.Ser680Asn (S(680)N) polymorphism in the FSHR gene with the outcome of COH.

DESIGN

Cohort study.

SETTING

Medical academy and hospital.

PATIENTS

A total of 1250 infertile Chinese women undergoing IVF/ICIS-ET treatment were included.

MEASURES

The association between an FSHR polymorphism (S(680)N) and the ovarian response was analysed. Genotyping was performed by utilizing direct sequencing and the Sequenom MassARRAY iPLEX platform. Follicular fluid oestradiol (E₂) and follicle-stimulating hormone (FSH) concentrations were determined using electrochemiluminesence immunoassays. The ovarian response parameters were analysed based on the FSHR genotypes. The odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated for the risk genotypes and alleles.

RESULTS

There were linear correlations between the basal FSH level, exogenous gonadotropin consumption, and oocytes retrieved and the Ser680 alleles. Patients in the homozygous SS group demonstrated higher basal FSH levels, required more dosage of exogenous gonadotropin for ovarian stimulation, and had fewer numbers of oocytes retrieved compared with patients in the homozygous NN and heterozygous groups. Logistic regression analysis revealed that the OR of a poor ovarian response for the NS genotype was 1·79 (95% CI 1·28-2·61; P < 0·001), whereas that for the SS genotype was 2·25 (95% CI 1·40-3·58; P < 0·001) after adjusting for age, BMI and basal FSH level. The concentration of E2 in the follicular fluid was significantly higher in subjects with the NN genotype than the SS genotype (772 ± 545 ng/ml vs. 1299 ± 504 ng/ml).

CONCLUSIONS

Follicle-stimulating hormone receptor gene polymorphism at position 680 is associated with different ovarian responses to controlled ovarian hyperstimulation.

Genome-wide association study of parity in Bangladeshi women

Human fertility is a complex trait determined by gene-environment interactions in which genetic factors represent a significant component. To better understand inter-individual variability in fertility, we performed one of the first genome-wide association studies (GWAS) of common fertility phenotypes, lifetime number of pregnancies and number of children in a developing country population. The fertility phenotype data and DNA samples were obtained at baseline recruitment from individuals participating in a large prospective cohort study in Bangladesh. GWAS analyses of fertility phenotypes were conducted among 1,686 married women. One SNP on chromosome 4 was non-significantly associated with number of children at P <10^-7 and number of pregnancies at P <10^-6. This SNP is located in a region without a gene within 1 Mb. One SNP on chromosome 6 was non-significantly associated with extreme number of children at P <10^-6. The closest gene to this SNP is HDGFL1, a hepatoma-derived growth factor. When we excluded hormonal contraceptive users, a SNP on chromosome 5 was non-significantly associated at P <10^-5 for number of children and number of pregnancies. This SNP is located near C5orf64, an open reading frame, and ZSWIM6, a zinc ion binding gene. We also estimated the heritability of these phenotypes from our genotype data using GCTA (Genome-wide Complex Trait Analysis) for number of children (h_g² = 0.149, SE = 0.24, p-value = 0.265) and number of pregnancies (h_g² = 0.007, SE = 0.22, p-value = 0.487). Our genome-wide association study and heritability estimates of number of pregnancies and number of children in Bangladesh did not confer strong evidence of common variants for parity variation. However, our results suggest that future studies may want to consider the role of 3 notable SNPs in their analysis.

Leutinizing hormone/choriogonadotropin receptor and follicle stimulating hormone receptor gene variants in polycystic ovary syndrome

PURPOSE

Previous studies identified follicle-stimulating hormone receptor (FSHR) and luteinizing hormone/choriogonadotropin receptor (LHCGR) genes as polycystic ovary syndrome (PCOS) susceptibility loci, which was dependent on the racial/ethnic background of studied population. We investigated the association of genetic variants in FSHR and LHCGR with PCOS in Bahraini Arab women.

METHODS

A retrospective case-control study, involving 203 women with PCOS, and 211 age- and ethnically-matched control women. FSHR and LHCGR genotyping was done by allelic exclusion method (real-time PCR).

RESULTS

Significantly lower frequencies of heterozygous LHCGR rs7371084 and FSHR rs11692782 genotype carriers were seen between women with PCOS vs. controls, and increased frequency of heterozygous homozygous LHCGR rs4953616 genotype carriers were detected between women with PCOS compared to control women. Limited linkage disequilibrium was noted among LHCGR and FSHR SNPs, and 2 blocks were constructed: the first (Block 1) spanning 61 kb contained the six tested LHCGR SNPs, and the second (Block 2) spanning 298 kb contained four of the five tested FSHR SNPs. Higher frequency of LHCGR GTCAAG haplotype was seen in women with PCOS compared to controls; the frequencies of the remaining LHCGR haplotypes, and all FSHR haplotypes were similar between cases and controls.

CONCLUSION

This is the first study to confirm the association of novel LHCGR (rs7371084, rs4953616) and FSHR (rs11692782) SNPs with PCOS. The differential association of LHCGR and FSHR variants with PCOS confirms the racial/ethnic contribution to their association with PCOS.

Early-life nutritional effects on the female reproductive system

There is now considerable epidemiological and experimental evidence indicating that early-life environmental conditions, including nutrition, affect subsequent development in later life. These conditions induce highly integrated responses in endocrine-related homeostasis, resulting in persistent changes in the developmental trajectory producing an altered adult phenotype. Early-life events trigger processes that prepare the individual for particular circumstances that are anticipated in the postnatal environment. However, where the intrauterine and postnatal environments differ markedly, such modifications to the developmental trajectory may prove maladaptive in later life. Reproductive maturation and function are similarly influenced by early-life events. This should not be surprising, because the primordial follicle pool is established early in life and is thus vulnerable to early-life events. Results of clinical and experimental studies have indicated that early-life adversity is associated with a decline in ovarian follicular reserve, changes in ovulation rates, and altered age at onset of puberty. However, the underlying mechanisms regulating the relationship between the early-life developmental environment and postnatal reproductive development and function are unclear. This review examines the evidence linking early-life nutrition and effects on the female reproductive system, bringing together clinical observations in humans and experimental data from targeted animal models.

Pharmacogenetics of ovarian response

Effective controlled ovarian stimulation (COS) is crucial for IVF outcome. Ovarian response to follicle-stimulating hormone, however, varies widely among women undergoing ovarian stimulation. Advance identification of patients who will elicit a poor or high response to standard treatment would be of great clinical benefit for such patients. Application of pharmacogenetics to ovarian response may predict stimulation success but also help in the adjustment and design of doses prior to treatment. Different studies have examined the impact of variations in follicle-stimulating hormone receptor, biochemical pathways involved in estrogen production and action, folliculogenesis and other aspects. Recently, gene-association studies have tried to identify a number of genetic variations affecting interindividual variability in COS.

Evaluating influence of the genotypes in the follicle-stimulating hormone receptor (FSHR) Ser680Asn (rs6166) polymorphism on poor and hyper-responders to ovarian stimulation: a meta-analysis

Background/aims

Reported associations of controlled ovarian hyperstimulation response (COH) with genotypes of the Ser680Asn (N680S) polymorphism in the follicle stimulating hormone receptor (FSHR) gene have conflicting results.

Methods

PubMed and Embase databases were searched for studies that investigated the N680S polymorphism in the FSHR gene in COH. Parameters used to examine ovarian response were poor and hyper-responses to COH. Using the meta-analytic approach, we estimated ovarian response risk (odds ratio [OR] with 95% confidence intervals) according to genotype.

Results

Our findings showed that SS genotype carriers were most likely to be poor responders (OR 1.61, p = 0.08) compared to the NN and NS genotypes which showed no associations (OR 0.93-0.95, p = 0.75-0.78). Heterogeneity of these pooled ORs warranted examining its sources. We detected outlying studies in each of the three N680S genotypes. Omitting these outliers erased the heterogeneity of the recalculated pooled outcomes. It also materially altered the SS effects where carriers became slightly unlikely to be poor responders (OR 0.90, p = 0.52). The S allele carrier effect was modulated for poor responders (OR 1.24, p = 0.39) in the Non-Hispanic Caucasian (NHC) subgroup. The likelihood of the S allele carriers (OR 1.47, p = 0.02) and the unlikelihood of the N allele carriers (OR 0.64, p = 0.007) were significant in our hyper-response findings. Confined to NHC retained significance of the S allele effects (OR 1.57, p = 0.01) but not among the N allele carriers (OR 0.68, p = 0.18).

Conclusions

In summary, this is a meta-analytical confirmation of the FSHR SS genotype role in COH response. Hyper-responder analysis strengths lie on the non-heterogeneity and robustness of its results. Non-robustness and heterogeneity of the poor-responder results compose its limitations. Thus, poor response findings probably require caution as to the interpretation as a susceptibility marker for ovarian response.

Electronic supplementary material

The online version of this article (doi:10.1186/s13048-014-0122-2) contains supplementary material, which is available to authorized users.

New insights into the genetic basis of infertility

Infertility is a disease of the reproductive system characterized by inability to achieve pregnancy after 12 or more months of regular unprotected sexual intercourse. A variety of factors, including ovulation defects, spermatogenic failure, parental age, obesity, and infections have been linked with infertility, in addition to specific karyotypes and genotypes. The study of genes associated with infertility in rodent models has expanded the field of translational genetics in identifying the underlying cause of human infertility problems. Many intriguing aspects of the molecular basis of infertility in humans remain poorly understood; however, application of genetic knowledge in this field looks promising. The growing literature on the genetics of human infertility disorders deserves attention and a critical concise summary is required. This paper provides information obtained from a systematic analysis of the literature related to current research into the genetics of infertility affecting both sexes.

Follicle-stimulating hormone receptor gene polymorphism in chronic anovulatory women, with or without polycystic ovary syndrome: a cross-sectional study

BACKGROUND

Polymorphisms at codons 307 and 680 are the most commonly encountered allelic variants of the follicle-stimulating hormone receptor (FSHR) gene. Studies in Caucasians suggest that certain FSHR variants are more common in women with polycystic ovary syndrome (PCOS) than normal women. The objective of this study was to determine the distribution of FSHR gene polymorphisms at codons 307 and 680 in Thai women with chronic anovulation, without (121 women) and with PCOS (133 women), using 132 known fertile women as controls.

METHODS

DNA samples from peripheral blood lymphocytes were extracted and analyzed by polymerase chain reaction-restriction fragment length polymorphism.

RESULTS

The prevalence of Threonine307Threonine (TT), Threonine307Alanine (TA), and Alanine307Alanine (AA) genotypes at codon 307 was 53.0% (95% CI = 44.2-61.7%), 42.4% (95% CI = 34-51.3%), and 4.5% (95% CI = 1.9-10.1%) in controls; 52.6% (95% CI = 43.8-61.3%), 39.8% (95% CI = 31.6-48.7%), and 7.5% (95% CI = 3.9-13.7%) in PCOS women; and 50.4% (95% CI = 42.8-61.2%), 45.4% (95% CI = 34.9-53.1%), and 4.5% (95% CI = 1.5-9.6%) in anovulatory women without PCOS, respectively. The prevalence of Asparagine680Asparagine (NN), Asparagine680Serine (NS), and Serine680Serine (SS) genotypes at codon 680 was 54.5% (95% CI = 45.7-63.2%), 40.9% (95% CI = 32.5-49.8%), and 4.5% (95% CI = 1.9-10.1%) in controls; 51.9% (95% CI = 43.1-60.6%), 44.4% (95% CI = 35.8-53.2%), and 3.8% (95% CI = 1.4-9.0%) in PCOS women; and 47.9% (95% CI = 40.4-58.8%), 47.1% (95% CI = 36.5-54.7%), and 5.0% (95% CI = 2-10.9%) in anovulatory women without PCOS, respectively. The prevalence of FSHR gene polymorphisms at both codons were not statistically different among the three groups.

CONCLUSIONS

In Thai women, there was no association between the FSHR gene polymorphism at codons 307 and 680 and chronic anovulation.

Luteinizing hormone and follicle stimulating hormone synergy: A review of role in controlled ovarian hyper-stimulation

Luteinizing hormone (LH) in synergy with follicle stimulating hormone (FSH) stimulates normal follicular growth and ovulation. FSH is frequently used in assisted reproductive technology (ART). Recent studies have facilitated better understanding on the complementary role of the LH to FSH in regulation of the follicle; however, role of LH in stimulation of follicle, optimal dosage of LH in stimulation and its importance in advanced aged patients has been a topic of discussion among medical fraternity. Though the administration of exogenous LH with FSH is obligatory for controlled ovarian stimulation in patients with hypogonadotropic hypogonadism, there is still a paucity of information of its usage in other patient population. In this review we looked in to the multiple roles that LH plays complementary to FSH to better understand the LH requirement in patients undergoing ART.

Quantitative methylation level of the EPHX1 promoter in peripheral blood DNA is associated with polycystic ovary syndrome

Steroid synthesis and metabolic pathways play important roles in the pathophysiology of PCOS, but until now there have been no studies on the methylation profiles of specific genes in steroid synthesis pathways that are known to be associated with PCOS. Here we used MassARRAY quantitative methylation analysis to determine the methylation levels of each CpG site or cluster in the promoters of EPHX1, SRD5A1, and CYP11A1 in 64 peripheral blood samples. We further examined the methylation level of EPHX1 in an independent cohort consisting of 116 people. Finally, we investigated the role of EPHX1 in steroidogenesis in the KGN cell line. For SRD5A1 and CYP11A1, there was no significant difference in methylation level between patients and controls. For EPHX1, however, the methylation levels of a few consecutive CpG sites and clusters were found to be significantly associated with PCOS. The methylation levels of a number of CpG clusters or sites were significantly lower in patients than in controls in the first cohort consisting of 64 people, such as clusters 13–14 (P<0.05), 15–16 (P<0.001), and 19–24 (P<0.001) and sites CpG_53 (P<0.01) and CpG_54 (P<0.05). Among differentiated methylation sites and clusters, the methylation levels of the CpG cluster 13–14 and CpG cluster 19–24 in PCOS patients were significantly lower than in controls in the second cohort of 116 people (P<0.05 for both). In addition, knockdown and overexpression experiments in KGN cells showed that EPHX1 can regulate estradiol concentrations, and this indicates a role for EPHX1 in steroidogenesis. Our study has demonstrated that methylation of the EPHX1 promoter might be associated with PCOS. This study provides direct evidence that methylation plays an important role in PCOS and demonstrates a novel role for EPHX1 in female reproduction.

Gene polymorphisms in female reproduction

This chapter presents an overview of the gene polymorphisms underlying the functions of ovarian receptors and their clinical implications in the female fecundity. A selection of genetic studies revealing significant associations between receptor polymorphisms, gene mutations, and some pathological conditions (i.e., female infertility, premature ovarian failure, polycystic ovary syndrome, endometriosis) are reviewed.

Association of -108 C>T PON1 polymorphism with polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is possibly the most common endocrine disorder in premenopausal women. In this study, we aimed to investigate the association of the -108 C>T polymorphism in the PON1 gene, which encodes the antioxidant enzyme paraoxonase-1, with PCOS. A total of 118 women with PCOS and 108 control subjects were included in this case-control study. The PON1 polymorphism was genotyped, biochemical and clinical parameters were determined and the correlations between the parameters were statistically evaluated. The differences in the PON1 allele and genotype distributions between PCOS patients and controls did not reach a statistical significance. The serum fasting glucose (GLU) levels did not differ significantly between the PCOS patients and the controls. However, the serum fasting insulin (INS) concentration, INS/GLU ratio and homeostasis model assessment (HOMA) index, although within the normal range, were significantly higher in the PCOS group. When considering PCOS patients and controls as separate groups or as a single group of patients, none of the analyzed biochemical or clinical parameters were found to be significantly correlated with the PON1 polymorphism. Therefore, the -108 C>T PON1 polymorphism was not found to be significantly associated with the presence of PCOS or with its particular clinical and biochemical characteristics in non-insulin resistant, non-obese patients.

Association of follicle-stimulating hormone receptor polymorphisms with ovarian response in Chinese women: a prospective clinical study

BACKGROUND

Follicular stimulating hormone (FSH) is a glycoprotein and widely used for the treatment of infertility; FSH action is mediated by FSH receptor (FSHR), SNPs of which determine the ovarian response. Two polymorphisms of the FSHR gene were identified, which caused a change of threonine (T) to alanine (A) at position 307 and asparagine (N) to serine(S) at position 680. Both polymorphic sites give rise to three discrete variants of the FSHR: TT, TA, and AA for position 307; NN, NS, and SS for position 680.

METHODOLOGY/PRINCIPAL FINDINGS

450 Chinese women were recruited in an assisted reproductive technology program from October 2011 to March 2012. FSHR polymorphisms at the positions 307 and 680 were examined by PCR-RFLP. Serum FSH and estradiol level, FSH amount, ovarian response and pregnancy rate were recorded during treatment. The basal FSH levels were higher in AA [7.38 ± 2.07 vs 6.34 ± 1.75, 6.63 ± 1.94, P<0.05, 95% CI (6.75, 8.01)] and SS [7.51 ± 2.01 vs 6.31 ± 1.75, 6.66 ± 1.96, P<0.05, 95% CI (6.88, 8.15)] compared to other genotypes respectively; the days for ovulation induction was slightly longer in AA and SS. Women with AA and SS have higher rates of poor response compared to carriers of other genotypes (P<0.05). Furthermore, there is a nearly complete linkage between these two polymorphisms in Chinese women (D'=0.95, r(2)=0.84).

CONCLUSIONS/SIGNIFICANCE

In Chinese women receiving ART, the subjects with AA and SS genotypes have higher basal FSH levels, and these genotypes are associated with an increased risk of poor response. Our data suggested that the personalized FSH therapy may be applied according to patient's genetic background in clinical settings. The linkage suggested that the polymorphisms of Thr307Ala and Asn680Ser may be used as TAG-SNP markers for analysis of potential genotyping in ART.

Association of the CAG repeat polymorphisms in androgen receptor gene with polycystic ovary syndrome: a systemic review and meta-analysis

BACKGROUND

Many studies have reported the associations of polymorphic CAG repeats in androgen receptor (AR) gene with PCOS risk, but with inconsistent results. So, the aim of present meta-analysis was to clarify such inconsistence, so as to provide more conclusive results.

METHODS

PubMed was searched for the eligible reports published until February 2012 without language limitation. The studies reporting the relationship between CAG repeat length and PCOS were selected for the meta-analysis according to the inclusion criteria. Two reviewers independently extracted the data and evaluated the study quality.

PRINCIPAL FINDINGS

As for the relationship between CAG repeat length and PCOS risk, the pooled results showed that the biallelic mean was not significantly different between PCOS and controls (SMD -0.03, 95% CI -0.16-0.10, P=0.603), and that the ORs of PCOS were not demonstrated for the individuals with the biallelic mean less than median (OR 0.96, 95% CI 0.68-1.35, P=0.794), with the short CAG allele (OR 0.94, 95% CI 0.80-1.10, P=0.424), or with the X-weighted biallelic mean (OR 0.81, 95% CI 0.46-1.41, P=0.447). Further, as for the relationship between CAG repeat length and T levels in PCOS patients, the biallelic mean was not significantly different between PCOS patients with high T and those with low T (SMD 0.79, 95% CI -0.12-1.70, P=0.088), while the summary correlation r indicated that the CAG biallelic mean appeared to be positively associated with T levels in PCOS (r 0.20, 95% CI 0.11-0.30, p=0.000).

CONCLUSIONS

This meta-analysis demonstrates no evident association between the CAG length variations in AR gene and PCOS risk, while the CAG length appears to be positively associated with T levels in PCOS patients.

The Polycystic Ovary Syndrome and recent human evolution

The Polycystic Ovary Syndrome (PCOS) is a complex endocrine disorder characterised both by reproductive and metabolic disturbance, and is the most common cause globally of ovarian infertility. It is also a familial polygenic condition, linked genetically to both Type 2 diabetes and the metabolic syndrome. The striking evolutionary paradox of this prominent genetically-based condition, which impairs fertility, is that not only should it have diminished in prevalence, but it should have done so rapidly - unless there has been some form of balancing selection. The emerging discipline of evolutionary medicine can provide important insights into the causes and patterns of occurrence of common diseases such as PCOS. In this paper we review the impacts of PCOS on infertility, fecundability and lifetime reproductive success and then critically appraise published hypotheses about the evolutionary origins of PCOS and related conditions.

Genetics of the polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a highly complex endocrine disorder, characterized by hyperandrogenemia, menstrual irregularities and polycystic ovaries. A strong genetic component to the etiology of PCOS is evident. However, due to the genetic and phenotypic heterogeneity of PCOS and the lack of insufficiently large cohorts, studies to identify specific contributing genes to date have yielded only few conclusive results. In this review we discuss the current status of the genetic analysis of PCOS including the results of numerous association studies with candidate genes involved in TGF-β and insulin signaling, type 2 diabetes mellitus and obesity susceptibility. Furthermore, we address current challenges in genetic studies of PCOS, and the promise of new approaches, including genome-wide association studies and next-generation sequencing.

Peroxisome proliferator activated receptor gamma gene variants influence susceptibility and insulin related traits in Indian women with polycystic ovary syndrome

PURPOSE

Peroxisome proliferator activated receptor gamma (PPARγ), a transcription factor involved in glucose and lipid metabolism is one of the candidate genes associated with polycystic ovary syndrome (PCOS). We investigated individual and combined associations of Pro12Ala and His447His polymorphisms of PPARγ with PCOS susceptibility and its related traits (hyperinsulinemia, hyperandrogenemia and lipid parameters) in Indian women.

METHOD

Genotyping of PPARγ polymorphisms in this case-control study was performed in PCOS (n = 450) and age-matched controls (n = 300) by direct sequencing. Clinical, anthropometric, hormonal and metabolic parameters were estimated in 275 women with PCOS and 169 controls. Chi-square test was used to compare the categorical data while regression analysis was used to evaluate association of genotypes with PCOS as well as its related phenotypes.

RESULTS

The frequencies of CC and CG + GG genotypes of Pro12Ala (χ² = 15.3, p < 0.0001) and CC and CT + TT genotypes of His447His (χ² = 12.7, p = 0.0004) polymorphisms were significantly different between PCOS and controls. Logistic regression analysis revealed a significant association of PCOS with Pro12Ala but not the His447His polymorphism. Carriers of variant genotypes at both PPARγ loci showed significantly reduced 2 h glucose levels while carriers of variant His447His genotype showed lower fasting insulin and HOMA-IR levels in PCOS women.

CONCLUSIONS

Pro12Ala polymorphism of PPARγ showed significant association with decreased PCOS susceptibility. Both polymorphisms influenced insulin related traits (2 h glucose, fasting insulin and HOMA-IR) and improved glucose metabolism in these women. This is the first report to establish that variations in PPARγ gene influence the insulin resistance pathophysiology in Indian women with PCOS.

Genetic association studies in female reproduction: from candidate-gene approaches to genome-wide mapping

Many genetic association studies have been performed to investigate disorders of female reproduction, such as polycystic ovary syndrome, premature ovarian failure and endometriosis. These disorders typically manifest heterogeneously, and their pathogeneses are influenced by polygenic and environmental factors. Researchers evaluating these genetic associations have chosen candidate genes related to hormone action, steroid biosynthesis, inflammatory cytokines and autoimmune factors. Several of these genes have yielded statistically significant associations with female reproductive disorders; however, few associations have been robust and reproducible. Whole-genome association studies generate more reliable and unbiased results and represent a breakthrough in genetic studies of female reproduction. Nevertheless, to date only a very small fraction of the overall heritability has been identified and so further studies are needed.