Polycystic ovary syndrome is not associated with polymorphisms of the TCF7L2, CDKAL1, HHEX, KCNJ11, FTO and SLC30A8 genes

Association of TCF7L2 genetic variants rs12255372 and rs7903146 with the polycystic ovary syndrome risk: systemic review and meta-analysis

BACKGROUND

A significant overlap in the pathophysiological features of polycystic ovary syndrome (PCOS) and type 2 diabetes mellitus (T2DM) has been reported; and insulin resistance is considered a central driver in both. The expression and hepatic clearance of insulin and subsequent glucose homeostasis are mediated by TCF7L2 via Wnt signaling. Studies have persistently associated TCF7L2 genetic variations with T2DM, however, its results on PCOS are sparse and inconsistent.

METHODS

We performed a comprehensive literature review of the data published till June 2024, on rs7903146, rs12255372, and PCOS in PubMed, Medline, the Cochrane Library, Google Scholar, Science Direct, Scopus, and Web of Science, followed by a meta-analysis to evaluate the association between these genetic variations and the PCOS risk. Using a random effects model, the pooled odds ratio (OR) and confidence intervals (95%CI) were computed using STATA statistical software.

RESULTS

The genotypic data from 3052 controls and 2291 women with PCOS from ten published studies were analysed. The results indicated no cumulative association between the rs7903146 variant and PCOS risk in either the allelic (C vs. T: OR = 1.21; 95% CI: 0.96-1.47, p > 0.05) or genotypic models (CC vs. CT + TT: OR = 1.06; 95% CI: 0.90-1.23, p > 0.05). Similarly, the genetic variant rs12255372 was not associated with PCOS risk both in the allelic and the dominant inheritance model(p > 0.05). Unlike East Asians (MAF < 0.025), both variants are highly frequent across other global populations including America, South Asia, and Europe (MAF ≥ 0.19).

CONCLUSION

Unlike T2DM, our results showed that rs7903146 and rs12255372 variants of the TCF7L2 gene do not modulate the PCOS risk. However, the role of other TCF7L2 variants remains to be studied in future studies.

Association of FTO gene variant rs9939609 with hyperandrogenemia and fasting glucose levels in South Indian women with polycystic ovarian syndrome

Background

Polycystic ovary syndrome (PCOS) is a common endocrine–metabolic disorder due to genetic and environmental factors. Genetic variants located in intron 1 of Fat mass and obesity-associated (FTO) gene are associated with increased risk of obesity and metabolic disorders. This study aims to investigate the association of common FTO polymorphism rs9939609 in South Indian women with PCOS to assess its association with metabolic and endocrine parameters. FTO genotyping was done on 100 PCOS patients and 70 controls by Sanger sequencing.

Results

The distribution of rs9939609 was observed between groups (28% TT, 57% TA, and 15% AA for PCOS and 37.1% TT, 51.4% TA, and 11.4% AA for the controls). In the PCOS group, across the carriers of different genotypes, a significant association was found between body mass index (BMI), fasting glucose levels, and testosterone with the presence of at least one risk allele of FTO rs9939609. Logistic regression analysis showed the association of fasting glucose levels and testosterone (OR 1.30 [1.03–1.63] and OR 5.83 [1.61–21.11], respectively) with FTO rs9939609.

Conclusions

Our findings indicated that FTO SNP rs9939609 was not associated with PCOS, but suggested a significant association of rs9939609 with hyperandrogenemia, fasting glucose levels, and BMI in South Indian women with PCOS.

Association of FTO gene variants rs9939609 and rs1421085 with polycystic ovary syndrome

Background

Polycystic ovary syndrome (PCOS) is among the most common complex genetic endocrinopathy, and its etiology and pathophysiology remain controversial. FTO is a large highly polymorphic gene and was coined as the first locus associated with adiposity. The association of the intronic variant FTO rs9939609 or FTO rs1421085 with PCOS has been controversial and unclear, mainly due to ethnic differences among populations. The present study aims to investigate the association of FTO rs9939609 or FTO rs1421085 polymorphisms with PCOS in Saudi Arabian women.

Results

A total of 98 PCOS patients and 99 healthy females were included in this study. PCR and genotyping (TaqMan®SNP Genotyping Assay) were employed. For FTO rs9939609, the genotype TA and the recessive model (TA + AA) in PCOS patients were significantly different compared with control subjects (p = 0.008 and p = 0.007, respectively). The allele frequency of the FTO rs9939609 gene variant was associated significantly (p = 0.027) with PCOS, suggesting that the A allele is a risk factor for PCOS susceptibility. However, for the FTO rs1421085 variant, the genotype and allele distributions did not differ significantly between PCOS patients and controls (p > 0.05).

Conclusions

This is the first report to study the association of FTO rs9939609 and FTO rs1421085 with PCOS in Saudi women. Results suggest that the FTO rs9939609 gene variant could be a genetic predisposing factor for PCOS Saudi women.

Genomic correlation, shared loci, and causal relationship between obesity and polycystic ovary syndrome: a large-scale genome-wide cross-trait analysis

BACKGROUND

The comorbidity between polycystic ovary syndrome (PCOS) and obesity has long been observed in clinical settings, but their shared genetic basis remains unclear.

METHODS

Leveraging summary statistics of large-scale GWAS(s) conducted in European-ancestry populations on body mass index (adult BMI, Nfemale=434,794; childhood BMI, N=39,620), waist-to-hip ratio (WHR, Nfemale=381,152), WHR adjusted for BMI (WHRadjBMI, Nfemale=379,501), and PCOS (Ncase=10,074, Ncontrol=103,164), we performed a large-scale genome-wide cross-trait analysis to quantify overall and local genetic correlation, to identify shared loci, and to infer causal relationship.

RESULTS

We found positive genetic correlations between PCOS and adult BMI (rg=0.47, P=2.19×10-16), childhood BMI (rg=0.31, P=6.72×10-5), and WHR (rg=0.32, P=1.34×10-10), all withstanding Bonferroni correction. A suggestive significant genetic correlation was found between PCOS and WHRadjBMI (rg=0.09, P=0.04). Partitioning the whole genome into 1703 nearly independent regions, we observed a significant local genetic correlation for adult BMI and PCOS at chromosome 18: 57630483-59020751. We identified 16 shared loci underlying PCOS and obesity-related traits via cross-trait meta-analysis including 9 loci shared between BMI and PCOS (adult BMI and PCOS: 5 loci; childhood BMI and PCOS: 4 loci), 6 loci shared between WHR and PCOS, and 5 loci shared between WHRadjBMI and PCOS. Mendelian randomization (MR) supported the causal roles of both adult BMI (OR=2.92, 95% CI=2.33-3.67) and childhood BMI (OR=2.76, 95% CI=2.09-3.66) in PCOS, but not WHR (OR=1.19, 95% CI=0.93-1.52) or WHRadjBMI (OR=1.03, 95% CI=0.87-1.22). Genetic predisposition to PCOS did not seem to influence the risk of obesity-related traits.

CONCLUSIONS

Our cross-trait analysis suggests a shared genetic basis underlying obesity and PCOS and provides novel insights into the biological mechanisms underlying these complex traits. Our work informs public health intervention by confirming the important role of weight management in PCOS prevention.

The genetic susceptibility profile of type 2 diabetes and reflection of its possible role related to reproductive dysfunctions in the southern Indian population of Hyderabad

BACKGROUND

The genetic association studies of type 2 diabetes mellitus (T2DM) hitherto undertaken among the Indian populations are grossly inadequate representation of the ethnic and geographic heterogeneity of the country. In view of this and due to the inconsistent nature of the results of genetic association studies, it would be prudent to undertake large scale studies in different regions of India considering wide spectrum of variants from the relevant pathophysiological pathways. Given the reproductive dysfunctions associated with T2DM, it would be also interesting to explore if some of the reproductive pathway genes are associated with T2DM. The present study is an attempt to examine these aspects in the southern Indian population of Hyderabad.

METHODS

A prioritized panel of 92 SNPs from a large number of metabolic and reproductive pathway genes was genotyped on 500 cases and 500 controls, matched for ethnicity, age and BMI, using AGENA MassARRAYiPLEX™ platform.

RESULTS

The allelic association results suggested 14 SNPs to be significantly associated with T2DM at P ≤ 0.05 and seven of those-rs2241766-G (ADIPOQ), rs6494730-T (FEM1B), rs1799817-A and rs2059806-T (INSR), rs11745088-C (FST), rs9939609-A and rs9940128-A (FTO)-remained highly significant even after correction for multiple testing. A great majority of the significant SNPs were risk in nature. The ROC analysis of the risk scores of the significant SNPs yielded an area under curve of 0.787, suggesting substantial power of our study to confer these genetic variants as predictors of risk for T2DM.

CONCLUSIONS

The associated SNPs of this study are known to be specifically related to insulin signaling, fatty acid metabolism and reproductive pathway genes and possibly suggesting the role of overlapping phenotypic features of insulin resistance, obesity and reproductive dysfunctions inherent in the development of diabetes. Large scale studies involving gender specific approach may be required in order to identify the precise nature of population and gender specific risk profiles for different populations, which might be somewhat distinct.

Association Between Polycystic Ovary Syndrome and the Polymorphisms of Aryl Hydrocarbon Receptor Repressor, Glutathione-S-transferase T1, and Glutathione-S-transferase M1 Genes

OBJECTIVE

To investigate the association between the aryl hydrocarbon receptor repressor (AhRR) C/G polymorphisms and glutathione-S-transferase M1 (GSTM1) and GSTT1 null mutation and the risk of polycystic ovary syndrome (PCOS) in Korean women.

METHODS

This was a case-control study of 478 women with PCOS and 376 aged-matched healthy controls. Genotyping of the AhRR C/G polymorphism and GSTM1 and GSTT1 were performed using real-time PCR analysis and multiplex PCR, respectively.

RESULTS

The genotype distribution of the AhRR C/G polymorphisms and GSTM1/GSTT1 null mutations did not differ between women with PCOS and controls. Using the wild-type combined AhRR CC and GSTT1 present genotype as a reference, the odds that a woman had PCOS were 1.54 (95% CIs 1.04-2.29) times higher if she had a combined AhRR CG or GG and GSTT1 null genotype. The odds that a woman had PCOS was 1.48 (95% CIs 1.08-2.04) times higher if she had a combined GSTM1/GSTT1 null genotype compared with the wild-type combined GSTM1/GSTT1 present genotype. However, there were no significant associations between the risk of PCOS and any combined AhRR and GSTM1.

CONCLUSIONS

Our data suggest that a combined AhRR CG or GG and GSTT1 null genotype or a combined GSTT1/GSTM1 null genotype might be associated with an increased risk of PCOS.

Skeletal Muscle Immunometabolism in Women With Polycystic Ovary Syndrome: A Meta-Analysis

Polycystic ovary syndrome (PCOS) is an endocrine and metabolic disorder affecting up to 15% of women at reproductive age. The main features of PCOS are hyperandrogenism and irregular menstrual cycles together with metabolic dysfunctions including hyperinsulinemia and insulin resistance and a 4-fold increased risk of developing type 2 diabetes. Despite the high prevalence the pathophysiology of the syndrome is unclear. Insulin resistance in women with PCOS likely affect the skeletal muscle and recently it was demonstrated that changes in DNA methylation affects the gene expression in skeletal muscle that in part can explain their metabolic abnormalities. The objective of this work was to combine gene expression array data from different datasets to improve statistical power and thereby identify novel biomarkers that can be further explored. In this narrative review, we performed a meta-analysis of skeletal muscle arrays available from Gene Expression Omnibus and from publications. The eligibility criteria were published articles in English, and baseline (no treatment) skeletal muscle samples from women with PCOS and controls. The R package Metafor was used for integration of the datasets. One hundred and fourteen unique transcripts were differentially expressed in skeletal muscle from women with PCOS vs. controls (q < 0.05), 87% of these transcripts have not been previously identified as altered in PCOS muscle. ING2, CDKAL1, and AKTIP had the largest differential increase in expression, and TSHZ2, FKBP2, and OCEL1 had the largest decrease in expression. Two genes, IRX3 and CDKAL1 were consistently upregulated (q < 0.05) in the individual analyses and meta-analysis. Based on the meta-analysis, we identified several dysregulated immunometabolic pathways as a part of the molecular mechanisms of insulin resistance in the skeletal muscle of women with PCOS. The transcriptomic data need to be verified by functional analyses as well as proteomics to advance our understanding of PCOS specific insulin resistance in skeletal muscle.

Genetic construction between polycystic ovarian syndrome and type 2 diabetes

Polycystic ovarian syndrome (PCOS) in reproductive-aged women is identified to be one of the endocrine disorders. This heterogeneous disorder is categorized through oligo-anovulation and hyperandrogenemia. National institutes of health and Rotterdam criterions were used to diagnose PCOS women. Type 2 Diabetes (T2D) is one of the complications in PCOS which is connected through insulin resistance (IR), which is a condition in which liver, muscles and fat infrequently respond to the hormones, and this leads to extreme IR and consequently leads to T2D disease. PCOS is inherited by the autosomal dominant mode of inheritance and may also with the different intricate patterns. Till now, many studies have been performed in PCOS with the genes identified by T2D and till now no studies have shown the similar genetic association and pathophysiology between both the diseases. So, the current review aims to investigate the genetic relation between PCOS and T2D and why both the diseases cannot be reverted. In this review, published data were screened with the T2D related genes and single nucleotide polymorphisms in PCOS women. The case-control, hospital-based and meta-analysis molecular studies disclosed both positive and negative connotations. Genetically, no relationship has been established between PCOS and T2D. Maximum studies have shown as PCOS women had developed T2D later in life because as a risk-factor, but none of the studies documented T2D women having developed PCOS as a risk factor. Apart from this, the disease PCOS is developed in women with reproductive age and T2D develops in both the men and women during adulthood. This review concludes as there is a genetic relation only in between PCOS and T2D, but not with T2D to PCOS and further it cannot be explicitly reverted from T2D to PCOS.

Association between FTO gene polymorphisms and type 2 diabetes mellitus, serum levels of apelin and androgen hormones among Iranian obese women

BACKGROUND AND AIMS

Recent studies show that FTO single nucleotide polymorphisms (SNPs) are associated with obesity and type 2 diabetes mellitus (T2DM). On the other hand, many animal models and clinical studies have demonstrated that apelin, an adipocytokine, is related to the obesity and T2DM. Additionally, obese women are at risk of Hyperandrogenemia. So, the aim of this study was to investigate the relationship between FTO variants (rs763967273, rs759031579, rs141115189, rs9926289, rs76804286 and rs9939609) with T2DM, serum apelin and androgenic hormones in Iranian obese women.

SUBJECTS AND METHODS

197 obese women (123 women with T2DM and 74 women as healthy control) were participated in this study. Anthropometrical and biochemical characteristics were measured. Serum apelin and androgen hormones levels were determined in 66 subjects consisting of 33 cases and 33 controls. PCR were carried out and subsequently, the PCR production was genotyped by Sanger sequencing assay.

RESULTS

Our observations showed that all SNPs are related to T2DM. The rs9926289 FTO variant had a strong association with serum apelin and dehydroepiandrosterone-sulfate levels (P=0.04 and P=0.03, respectively) among SNPs. In addition, apelin and androgenic hormones were correlated with T2DM. Two polymorphisms including rs9939609 and rs9926289 had a strong Linkage disequilibrium (r²=1).

CONCLUSION

FTO variants not only were associated with T2DM, but also some variants had a strong association with apelin and androgenic hormones profile.

Association of type 2 diabetes mellitus genes in polycystic ovary syndrome aetiology among women from southern India

BACKGROUND & OBJECTIVES

Polycystic ovary syndrome (PCOS) is the most common reproductive endocrine disorder of premenopausal women. Given the phenotypic overlap between PCOS and type 2 diabetes mellitus (T2DM), this study was carried out to investigate whether genes implicated in T2DM were also involved in the susceptibility to PCOS among women from southern India.

METHODS

A total of 248 women with PCOS and 210 healthy women as controls were genotyped for a panel of 15 single nucleotide polymorphisms (SNPs) from the nine T2DM genes, such as TCF7L2, IGF2BP2, SLC30A8, HHEX, CDKAL1, CDKN2A, IRS1, CAPN10 and PPARG, on Sequenom MassARRAY platform.

RESULTS

None of the 15 SNPs were found to be significantly associated with PCOS after Bonferroni correction for multiple testing, either in the univariate or multivariate context. The cumulative effect of risk alleles observed with reference to T2DM was also not seen with reference to PCOS.

INTERPRETATION & CONCLUSIONS

The nine T2DM genes considered in this exploratory study might not be the primary susceptibility factors for PCOS among Indian women. Our results supplement the lack of evidence of the association of T2DM genes with PCOS among the Chinese and Caucasians hinting at the possible universality of this pattern. Specifically designed comprehensive studies that include women with T2DM and PCOS are required to explore the precise role of the diabetes genes.

Single nucleotide polymorphisms in the TGF-β1 gene are associated with polycystic ovary syndrome susceptibility and characteristics: a study in Korean women

PURPOSE

Although many hypotheses regarding the pathogenesis of polycystic ovary syndrome (PCOS) have been generated, genetic studies have not identified specific genes that play a role in PCOS etiopathogenesis. This study aimed to investigate the relationship between TGF-β1 gene polymorphism and PCOS in Koreans.

METHOD

A total of 51 Korean women with PCOS and 69 healthy women were enrolled. We analyzed 4 single nucleotide polymorphisms (SNPs) of the TGF-β1 gene (rs11466313, rs1800469, rs2317130, and rs4803457). We also analyzed laboratory measurements, such as free testosterone, glucose, and cholesterol.

RESULTS

The frequencies of rs1800469T allele negativity, rs4803457T allele negativity, the rs1800469CC genotype, and the rs4803457CC genotype showed positive associations with PCOS (P = 0.003, P = 0.027, P = 0.009, and P=0.031, respectively), whereas the haplotypes rs1800469C-rs4803457T and rs1800469T-rs4803457T showed negative associations with PCOS. A strong protective effect of the "rs1800469CT-rs4803457TT" combination (OR = 0.09) and a strong risk effect of "rs1800469CC-rs4803457CC" (OR = 6.23) for PCOS were observed. The rs1800469C/T and rs2317130C/T SNPs exhibited associations with several laboratory measurements with various levels of significance.

CONCLUSION

The results demonstrated an association of TGF-β1 gene polymorphisms with the development and/or characteristics of PCOS in the Korean population.

Genetic determinants of polycystic ovary syndrome: progress and future directions

The field of the genetics of polycystic ovary syndrome (PCOS) has relatively recently moved into the era of genome-wide association studies. This has led to the discovery of 16 robust loci for PCOS. Some loci contain genes with clear roles in reproductive (LHCGR, FSHR, and FSHB) and metabolic (INSR and HMGA2) dysfunction in the syndrome. The next challenge facing the field is the identification of causal variants and genes and the role they play in PCOS pathophysiology. The potential for gene discovery to improve diagnosis and treatment of PCOS is promising, though there is much to be done in the field before the current findings can be translated to the clinic.

Is the association between insulin resistance and diabetogenic haematopoietically expressed homeobox (HHEX) polymorphism (rs1111875) affected by polycystic ovary syndrome status?

Polycystic ovary syndrome (PCOS) is frequently accompanied by insulin resistance (IR). The aim of the present study was to investigate whether the genetic association between insulin resistance and two single nucleotide polymorphisms (SNPs), namely rs7903146 (C/T) in transcription factor 7-like 2 (TCF7L2) and rs1111875 (A/G) in haematopoietically expressed homeobox (HHEX), is affected by PCOS status in Iranian women. The study participants consisted of 582 women with PCOS (cases) referred to the Reproductive Endocrinology Research Center and 504 subjects without PCOS (controls), randomly selected from the Tehran Lipid and Glucose Study. Cases and controls were further subdivided to two groups according to IR status: those with and without IR. IR was identified on the basis of homeostasis model assessment of insulin resistance (HOMA-IR) ≥2.63. The SNPs in TCF7L2 and HHEX were genotyped by polymerase chain reaction-restriction fragment length polymorphism. There were no significant differences in the distribution of genotypes and alleles between cases and controls (P<0.05). Among cases, the prevalence of the CC, CT and TT genotypes was 37.8%, 46.3% and 15.9%, respectively, whereas the prevalence of the AA, AG and GG genotypes was 13.5%, 46.1% and 40.4%, respectively. In the control group, the prevalence of the CC, CT and TT genotypes was 32.2%, 53.9% and 13.9%, respectively, whereas the prevalence of the AA, AG and GG genotypes was 11.3%, 48.6% and 40.0%, respectively. After adjustment for age and body mass index, the probability of IR was decreased by 49% among carriers of the A allele in the control group (95% confidence interval 0.33-0.78; P=0.002). The findings of the present study suggest that the association between IR and diabetogenic polymorphisms may be affected by PCOS status.

Association between rs7903146 and rs12255372 polymorphisms of transcription factor 7-like 2 gene and polycystic ovary syndrome: a systematic review and meta-analysis

The present systematic review and meta-analysis of case-control studies examines the associations between rs7903146 and rs12255372 polymorphisms of the TCF7L2 gene and PCOS. A search of the literature published until August 2014 was carried out in PubMed, Cochrane Central Register of Controlled Trials, EMBASE, and LILACS. There were no other limits except for the end date. We included observational studies with women of any age diagnosed with PCOS and healthy controls that analyzed polymorphisms rs7903146 and rs12255372. We included case-control or cross-sectional studies analyzing polymorphism rs7903146 or rs12255372 in women with PCOS and healthy controls. Eighteen studies were identified after the primary literature search and seven articles were included in the meta-analysis. All employed Rotterdam criteria for the diagnosis of PCOS. The genotypic distributions in the control groups were in agreement with Hardy-Weinberg equilibrium in all studies. The pooled population included Asian descendents (Chinese, Korean), Caucasians from southern Brazil, Tunisian, and European populations (British/Irish, Northern Finns, Greeks, Czechs), including 1,892 women with PCOS and 2,695 controls. There were no significant associations between PCOS and TCF7L2 rs7903146 or rs12255372 polymorphisms, irrespective of whether allele contrast, additive, dominant, or recessive models of inheritance were used. Furthermore, no significant associations were found after stratification for ethnicity (Asian or non-Asian). There was no significant heterogeneity between studies and no publication bias. The present results suggest that rs7903146 T allele or rs12255372 is not associated with risk for PCOS in non-Asian or Asian women. This systematic review and meta-analysis are registered in PROSPERO under number CRD42013005930.

FTO gene variants are not associated with polycystic ovary syndrome in women from Southern Brazil

BACKGROUND AND AIMS

Polycystic ovary syndrome (PCOS) is a common endocrine disorder, presenting polygenic traits as well as determined by environmental factors. Given the overlap between PCOS and obesity, we assessed the frequencies of SNPs rs9939609 and rs8050136 in intron 1 of the FTO gene and their haplotypes in women with PCOS and healthy controls with regular cycles from Southern Brazil and investigated their relationship with metabolic traits and endocrine parameters.

SUBJECTS AND METHODS

The sample comprised 298 women (199 with PCOS and 99 non-hirsute women with regular ovulatory cycles). FTO genotyping was done by real-time PCR. Haplotypes were constructed from the combination of both polymorphisms. Frequencies were inferred using PHASE 2.1.1 software.

RESULTS

The distribution of rs9939609 (PCOS: 32.6% TT, 45.9% TA, 21.5% AA; controls: 33.3% TT, 49.0% TA, 17.7% AA) and rs8050136 (PCOS: 21.7% AA, 43.3% AC, 35.0% CC; controls: 14.9% AA, 48.9% AC, 36.2% CC) was similar between groups. The mean age of participants was 22.7±7.1years. Women with PCOS had significantly higher BMI, waist circumference, total testosterone, and FAI vs. controls. In the PCOS group, no differences between genotypes and haplotypes were found for clinical variables. The presence of at least one risk allele for polymorphisms rs9939609 and rs8050136 was associated with higher fasting glucose levels.

CONCLUSION

Our findings indicate that neither the FTO rs9939609 and rs8050136 polymorphisms nor its haplotypes are related to PCOS, but suggest an association between the presence of risk alleles of SNPs rs9939609 and rs8050136 in FTO and glucose levels in women from Southern Brazil.

Genome-wide association study identified new susceptibility loci for polycystic ovary syndrome

STUDY QUESTION

Are there any novel genetic markers of susceptibility to polycystic ovary syndrome (PCOS)?

SUMMARY ANSWER

We identified a novel susceptibility locus on chromosome 8q24.2 and several moderately associated loci for PCOS in Korean women.

WHAT IS KNOWN ALREADY

PCOS is a highly complex disorder with significant contributions from both genetic and environmental factors. Previous genome-wide association studies (GWAS) in the Han Chinese population identified several risk loci for PCOS. However, GWAS studies on PCOS remain very few. The aim of this study was to identify novel markers of susceptibility to PCOS through GWAS.

STUDY DESIGN, SIZE, DURATION

A two-stage GWAS was conducted. The initial discovery set for GWAS consisted of 976 PCOS cases and 946 controls. The second stage (replication study) included 249 PCOS cases and 778 controls.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Patients were diagnosed according to the Rotterdam criteria. Genomic DNAs were genotyped using the HumanOmni1-Quad v1 array. In the replication stage, the 21 most promising signals selected from the discovery stage were tested for their association with PCOS.

MAIN RESULTS AND THE ROLE OF CHANCE

One novel locus with genome-wide significance and seven moderately associated loci for PCOS were identified. The strongest association was on chromosome 8q24.2 (rs10505648, OR = 0.52, P = 5.46 × 10(-8)), and other association signals were located at 4q35.2, 16p13.3, 4p12, 3q26.33, 9q21.32, 11p13 and 1p22 (P = 5.72 × 10(-6)-6.43 × 10(-5)). The strongest signal was located upstream of KHDRBS3, which is associated with telomerase activity, and could drive PCOS and related phenotypes.

LIMITATIONS, REASONS FOR CAUTION

The limitation of our study is the modest sample size used in the replication cohort. The limited sample size may contribute to a lack of statistical power to detect an association or show a trend in severity.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings provide new insight into the genetics and biological pathways of PCOS and could contribute to the early diagnosis and prevention of metabolic and reproductive morbidities.

STUDY FUNDING/COMPETING INTERESTS

This work was supported in part by the grant from the Korea Centers for Disease Control and Prevention (2009-E00591-00). The work was also supported by the Ewha Global Top5 Grant 2013 of Ewha Womans University. None of the authors has any conflict of interest to declare.

FTO Gene Variants Are Associated with PCOS Susceptibility and Hyperandrogenemia in Young Korean Women

BACKGROUND

The fat mass and obesity-associated (FTO) gene is associated with obesity and type 2 diabetes mellitus. Obesity and insulin resistance are also common features of polycystic ovary syndrome (PCOS). Therefore, the FTO gene might be a candidate gene for PCOS susceptibility. The aim of the present study was to evaluate the effects of FTO gene variants on PCOS susceptibility and metabolic and reproductive hormonal parameters.

METHODS

We recruited 432 women with PCOS (24±5 years) and 927 healthy women with regular menstrual cycles (27±5 years) and performed a case-control association study. We genotyped the single nucleotide polymorphisms rs1421085, rs17817449, and rs8050136 in the FTO gene and collected metabolic and hormonal measurements.

RESULTS

Logistic regression revealed that the G/G genotype (rs1421085, 1.6%), the C/C genotype (rs17817449, 1.6%), and the A/A genotype (rs8050136, 1.6%) were strongly associated with an increased risk of PCOS (odds ratio, 2.551 to 2.559; all P<0.05). The strengths of these associations were attenuated after adjusting for age and BMI. The women with these genotypes were more obese and exhibited higher free androgen indices (P<0.05) and higher free testosterone levels (P=0.053 to 0.063) compared to the other genotypes. However the significant differences disappeared after adjusting for body mass index (BMI). When we analyzed the women with PCOS and the control groups separately, there were no significant differences in the metabolic and reproductive hormonal parameters according to the FTO gene variants.

CONCLUSION

The rs1421085, rs17817449, and rs8050136 variants of the FTO gene were associated with PCOS susceptibility and hyperandrogenemia in young Korean women. These associations may be mediated through an effect of BMI.

Gene dose effect between a fat mass and obesity-associated polymorphism and body mass index was observed in Korean women with polycystic ovary syndrome but not in control women

OBJECTIVE

To examine the association between fat mass and obesity-associated (FTO) polymorphisms and polycystic ovary syndrome (PCOS) in Korean women.

DESIGN

Case-control study.

SETTING

University department of obstetrics and gynecology.

PATIENT(S)

Women with (n = 552) or without (n = 559) PCOS.

INTERVENTION(S)

Genotyping was performed.

MAIN OUTCOME MEASURE(S)

FTO rs9939609 genotype distribution and correlation between variants in this gene and PCOS phenotypes.

RESULT(S)

The mean body mass index (BMI) of the patients was significantly higher than that of the control subjects (22.0 ± 4.1 kg/m(2) vs. 20.1 ± 2.5 kg/m(2)), but most (81.3%) of the patients were not obese. FTO rs9939609 was not significantly associated with PCOS itself. However, a positive correlation was observed between the number of variant alleles and BMI in women with PCOS: Each additional copy of the variant allele increased BMI by a mean (95% confidence interval) of 4.8% (1.4%-8.3%) or 1.11 kg/m(2) (1.03-1.20 kg/m(2)) after adjusting for age. This correlation was not observed in the control subjects.

CONCLUSION(S)

FTO rs9939609 was not a major determinant of PCOS. However, in the women with PCOS who were primarily nonobese, a gene dose effect was observed for BMI. The FTO gene may play an influential role in predisposition to PCOS via an association with obesity.

Relationships between TCF7L2 genetic polymorphisms and polycystic ovary syndrome risk: a meta-analysis

OBJECTIVE

This meta-analysis was performed to evaluate the relationships between genetic polymorphisms in the TCF7L2 gene and polycystic ovary syndrome (PCOS) risk.

METHODS

The PubMed, Centralised Information Service for Complementary Medicine (CISCOM), Cumulative Index to Nursing and Allied Health Literature (CINAHL), Web of Science, Google Scholar, EBSCO, Cochrane Library, and Common Biorepository Model (CBM) databases were searched for relevant articles published before November 1st, 2013, without language restrictions. Meta-analysis was conducted using the STATA 12.0 software. The relationships were evaluated by calculating the pooled odds ratios (ORs) and their 95% confidence intervals (CIs). Seven case-control studies with a total 2458 PCOS patients and 5109 healthy subjects' met our inclusion criteria for qualitative data analysis. Two common polymorphisms (rs7903146 C→T and rs12255372 G→T) in the TCF7L2 gene were assessed.

RESULTS

The results of our meta-analysis suggested that TCF7L2 genetic polymorphisms might be strongly correlated with an increased risk of PCOS (allele model, OR=1.33, 95% CI=1.15-1.54, P<0.001; dominant model, OR=1.40, 95% CI=1.12-1.75, P=0.003), especially for the rs7903146 C→T polymorphism. A subgroup analysis was done to investigate the effect of ethnicity on an individual's risk of PCOS. Our results revealed positive significant correlations between TCF7L2 genetic polymorphisms and an increased risk of PCOS among Caucasians (allele model, OR=1.26, 95% CI=1.08-1.47, P=0.004; dominant model, OR=1.33, 95% CI=1.00-1.76, P=0.046) and Asians (allele model, OR=2.02, 95% CI=1.42-2.89, P<0.001; dominant model, OR=2.02, 95% CI=1.40-2.92, P<0.001), but not among Africans (all P<0.05).

CONCLUSIONS

Our findings provide convincing evidence that TCF7L2 genetic polymorphisms may contribute to susceptibility to PCOS, especially for the rs7903146 C→T polymorphism among Caucasians and Asians.

Association between fat mass- and obesity-associated (FTO) gene polymorphism and polycystic ovary syndrome: a meta-analysis

Aims

Many studies have investigated the relationship between FTO gene polymorphism and polycystic ovary syndrome (PCOS) susceptibility but revealed mixed results. In this study, we aimed to perform a meta-analysis to clarify this association.

Methods

Published literature from PubMed, Embase and CNKI was retrieved. Meta-analysis was performed to calculate pooled odds ratio (OR) with 95% confidence interval (CI) using the random- or fix- effects model.

Results

A total of 5 studies (4778 cases and 4272 controls) were included in our meta-analysis. The results suggested that FTO rs9939609 polymorphism (or its proxy) was marginally associated with PCOS risk after adjustment for body mass index (BMI) (OR = 1.26; 95%CI: 1.02–1.55). However, the marginal association was not stable after sensitivity analysis. In the subgroup analysis by ethnicity, the association was significant in East Asians (OR = 1.43, 95%CI = 1.30–1.59) but not in Caucasians (OR = 1.04, 95%CI = 0.85–1.29).

Conclusions

Our present meta-analysis indicated that FTO rs9939609 polymorphism (or its proxy) might not be associated with risk of PCOS in overall population. However, in East Asians, there might be a direct association between FTO variant and PCOS risk, which is independent of BMI (adiposity).

Polymorphisms of TCF7L2 gene in South Brazilian women with polycystic ovary syndrome: a cross-sectional study

OBJECTIVE

To assess whether TCF7L2 single nucleotide polymorphisms rs7903146 C/T and rs11196236 C/T are associated with polycystic ovary syndrome (PCOS) in South Brazilian women.

DESIGN

Cross-sectional study.

METHODS

Two hundred PCOS patients and 102 non-hirsute, ovulatory controls were genotyped by real-time PCR. Haplotypes were constructed from the combination of both polymorphisms. Frequencies were inferred using the PHASE 2.1.1 software.

RESULTS AND CONCLUSIONS

The distribution of rs7903146 (PCOS, 54.4% CC; 28.5% CT; 17.1% TT; controls, 51.0% CC; 37.0% CT; 12.0% TT) and rs11196236 (PCOS, 4.3% CC; 33.5% CT; 62.2% TT; controls, 3.2% CC; 35.5% CT; 61.3% TT) was similar between the groups. rs7903146 and rs11196236 were not in linkage disequilibrium (|D'|=0.34; r(2)=0.07). PCOS participants were younger, with higher age-adjusted BMI, waist circumference, blood pressure, triglycerides, insulin, homeostasis model assessment index to estimate insulin resistance and total testosterone, and lower HDL-C and sex hormone binding globulin vs controls. In PCOS, no differences between genotypes and haplotypes were found for clinical and metabolic variables. However, for each T (rs7903146) and T (rs11196236) allele added to the haplotypes, a variation of 5.87 cm in waist (P trend=0.01), 10.7 mg/dl in total cholesterol (P trend=0.03), and 10.3 mg/dl in LDL-C (P trend=0.01) was recorded. TCF7L2 variants are probably not implicated in PCOS development in South Brazilian women.

Polymorphisms of transcription factor-7-like 2 (TCF7L2) gene in Tunisian women with polycystic ovary syndrome (PCOS)

BACKGROUND AND AIMS

Polycystic ovary syndrome (PCOS) is a common endocrine disorder that affects women in their child-bearing age, and is often associated with insulin resistance and type 2 diabetes (T2DM). Given the overlap between PCOS and T2DM, we investigated the association of transcription factor-7-like 2 (TCF7L2) variants rs4506565, rs7903146, rs12243326, and rs12255372 with the susceptibility to PCOS.

SUBJECTS AND METHODS

Study subjects comprised 119 Tunisian women with PCOS (mean age 29.8±4.7years), and 150 control women (mean age 30.6±5.9years). TCF7L2 genotyping was done by the allelic discrimination/real-time PCR method.

RESULTS

Minor allele frequencies (MAFs) of rs4506565 (P=0.61), rs7903146 (P=0.68), rs12243326 (P=0.56), and rs12255372 (P=0.60) were comparable between PCOS cases and control subjects. As the four tested TCF7L2 variants were in linkage disequilibrium, 4-locus (rs4506565, rs7903146, rs12243326, rs12255372) haplotype analysis demonstrated that haplotype 2111 was initially negatively associated with PCOS [P=0.035; OR (95% CI)=0.13 (0.02-0.85)], which was later lost upon correcting for multiple comparisons [Pc=0.248].

CONCLUSION

Our data suggest that there is weak or no contribution of TCF7L2 gene polymorphism to PCOS in Tunisian women. Further studies with larger samples are necessary to confirm this observation.

Common variant rs9939609 in gene FTO confers risk to polycystic ovary syndrome

BACKGROUND

Fat mass and obesity-associated gene (FTO) has been associated with obesity, especially the common variant rs9939609. Polycystic ovary syndrome (PCOS) is a complex endocrine-metabolic disorder and over 50% of patients are overweight/obese. Thus FTO is a potential candidate gene for PCOS but their relationship is confusing and remains to be clarified in different population with a large sample size.

METHOD

This study was performed adopting a two-stage design by genotyping SNP rs9939609. The first set comprise of 741 PCOS and 704 control subjects, with data from our previous GWAS. The second phase of replication study was performed among another independent group of 2858 PCOS and 2358 control subjects using TaqMan-MGB probe assay. All subjects are from Han Chinese.

RESULTS

The less meaningful association of FTO rs9939609 and PCOS discovered in GWAS (P = 2.47E-03), was further confirmed in the replication study (P = 1.86E-09). Using meta-analysis, the P-meta value has reached 6.89E-12, over-exceeding the genome-wide association level of 5.00E-8. By combination, the P value was 1.26E-11 and after BMI adjustment it remained significant(P = 1.82E-06). To further elucidate whether this association is resulted from obesity or PCOS per se, the samples were divided into two groups-obese and non-obese PCOS, and the results were still positive in obese group (P obese = 5.81E-05, OR = 1.55), as well as in non-obese PCOS group (P non-obese = 7.06E-04, OR = 1.28).

CONCLUSION

Variant rs9939609 in FTO is associated with PCOS in Chinese women, not only in obese PCOS subjects, but also in non-obese cases.

Phenotyping clinical disorders: lessons learned from pelvic organ prolapse

Genetic epidemiology, the study of genetic contributions to risk for disease, is an innovative area in medicine. Although research in this arena has advanced in other disciplines, few genetic epidemiological studies have been conducted in obstetrics and gynecology. It is crucial that we study the genetic susceptibility for issues in women's health because this information will shape the new frontier of personalized medicine. To date, preterm birth may be one of the best examples of genetic susceptibility in obstetrics and gynecology, but many areas are being evaluated including endometriosis, fibroids, polycystic ovarian syndrome, and pelvic floor disorders. An essential component to genetic epidemiological studies is to characterize, or phenotype, the disorder to identify genetic effects. Given the growing importance of genomics and genetic epidemiology, we discuss the importance of accurate phenotyping of clinical disorders and highlight critical considerations and opportunities in phenotyping, using pelvic organ prolapse as a clinical example.

Diagnosis and treatment of polycystic ovarian syndrome in adolescents

PURPOSE OF REVIEW

To review what is understood about the pathophysiology of polycystic ovarian syndrome (PCOS), the diagnostic challenges of PCOS in adolescent women, associated risk factors, as well as the best evidence-based treatment options for adolescence.

RECENT FINDINGS

Diagnosing PCOS in adolescents requires a unique set of criteria for which no single marker currently exists. Adolescents at high risk for developing the syndrome are congenital virilization, low birth weight, premature pubarche, central precocious puberty, large for gestational age girls born to overweight mothers, obesity syndromes, insulin-resistant features, and girls born to parents with PCOS, central obesity, or diabetes in whom PCOS ought to be suspected when associated with irregular menses. Insulin, hyperandrogenemia, and adipocytokines are integral players in the pathophysiology of PCOS. PCOS may be an inheritable trait; however, no gene has yet been identified. Quality of life remains a concern for young women with PCOS. Lifestyle modifications geared to prevent long-term sequelae remain the first-line treatment in conjunction with oral contraceptive pills.

SUMMARY

Identifying PCOS in adolescents remains a diagnostic dilemma, but early intervention and treatment can improve long-term health.

Genome-wide association study identifies GYS2 as a novel genetic factor for polycystic ovary syndrome through obesity-related condition

To investigate the role of genetic predisposition in the pathogenesis of polycystic ovary syndrome (PCOS) in relation to obesity, we performed a genome-wide association study of PCOS in Koreans (n=1741). PCOS is a heterogeneous endocrinal disorder of uncertain etiology. Obesity is one of the well-known risk factors for PCOS. Genome-wide association study. Women with or without PCOS. A total of 1881 samples were genotyped using Illumina HumanOmni1 Quad v1 and processed by R packages. The PCOS patients were divided into two subgroups according to PCOS diagnostic criteria (Rotterdam and National Institutes of Health (NIH)). For PCOS-associated loci in the two definitions, we successfully confirmed significant associations of GYS2 for body mass index in the discovery stage. We further replicated pleiotropic associations of GYS2 in a childhood obesity study (n=482) and in a gestational diabetes study (n=1710), respectively. Our study provides a preliminary framework upon diverse genetic effects underlying PCOS in Korean women. A newly identified GYS2 gene as a predisposing factor of PCOS might expand understanding of the biological pathways in metabolic and endocrine regulation.