Evidence for association of polycystic ovary syndrome in caucasian women with a marker at the insulin receptor gene locus

Deconstructing a Syndrome: Genomic Insights Into PCOS Causal Mechanisms and Classification

Polycystic ovary syndrome (PCOS) is among the most common disorders in women of reproductive age, affecting up to 15% worldwide, depending on the diagnostic criteria. PCOS is characterized by a constellation of interrelated reproductive abnormalities, including disordered gonadotropin secretion, increased androgen production, chronic anovulation, and polycystic ovarian morphology. It is frequently associated with insulin resistance and obesity. These reproductive and metabolic derangements cause major morbidities across the lifespan, including anovulatory infertility and type 2 diabetes (T2D). Despite decades of investigative effort, the etiology of PCOS remains unknown. Familial clustering of PCOS cases has indicated a genetic contribution to PCOS. There are rare Mendelian forms of PCOS associated with extreme phenotypes, but PCOS typically follows a non-Mendelian pattern of inheritance consistent with a complex genetic architecture, analogous to T2D and obesity, that reflects the interaction of susceptibility genes and environmental factors. Genomic studies of PCOS have provided important insights into disease pathways and have indicated that current diagnostic criteria do not capture underlying differences in biology associated with different forms of PCOS. We provide a state-of-the-science review of genetic analyses of PCOS, including an overview of genomic methodologies aimed at a general audience of non-geneticists and clinicians. Applications in PCOS will be discussed, including strengths and limitations of each study. The contributions of environmental factors, including developmental origins, will be reviewed. Insights into the pathogenesis and genetic architecture of PCOS will be summarized. Future directions for PCOS genetic studies will be outlined.

A brief insight into the etiology, genetics, and immunology of polycystic ovarian syndrome (PCOS)

Polycystic ovarian syndrome (PCOS) is a prevailing endocrine and metabolic disorder occurring in about 6-20% of females in reproductive age. Most symptoms of PCOS arise early during puberty. Since PCOS involves a combination of signs and symptoms, thus it is considered as a heterogeneous disorderliness. The most accepted diagnostic criteria is Rotterdam criteria which involves two of the latter three features: (a) hyperandrogenism, (b) oligo- or an-ovulation, and (c) polycystic ovaries. The persistent hormonal imbalance leads to multiple small antral follicles formation and irregular menstrual cycle, ultimately causing infertility among females. Insulin resistance, cardiovascular diseases, abdominal obesity, psychological disorders, infertility, and cancer are also related to PCOS. These pathophysiologies associated with PCOS are interrelated with each other. Hyperandrogenism causes insulin resistance and hyperglycemia, leading to ROS formation, oxidative stress, and abdominal adiposity. In consequence, inflammation, ROS production, insulin resistance, and hyperandrogenemia also increase. Elevation of AGEs in the body either produced endogenously or consumed from diet exaggerates PCOS symptoms and is also related to ovarian dysfunction. This review summarizes how AGE formation, inflammation, and oxidative stress are significantly essential in PCOS progression. Alterations during prenatal development like exposure to excess AMH, androgens, or toxins (bisphenol-A, endocrine disruptors, etc.) may also be the etiologic mechanism behind PCOS. Although the etiology of this disorder is unclear, environmental and genetic factors are primarily involved. Physical inactivity, as well as unhealthy eating habits, has a vital role in the progression of PCOS. This review outlines a collection of specific genes phenotypically linked with PCOS. Furthermore, beneficial effect of metformin in maintaining endocrine abnormalities and ovarian function is also mentioned. Kisspeptin is a protein which helps in onset of puberty and increases GnRH pulsatile release during ovulation as well as role of KNDy neurons in GnRH pulsatile signal required for reproduction are also elaborated. This review also focuses on the immunology related to PCOS involving chronic low-grade inflammation, and how the alterations within the follicular microenvironment are intricated in the development of infertility in PCOS patients. How PCOS develops following antiepileptic and psychiatric medication is also expanded in this review. Initiation of antiandrogen treatment in early age (≤ 25 years) might be helpful in spontaneous conception in PCOS women. The role of BMP (bone morphogenetic proteins) in folliculogenesis and their expression in oocytes and granulosa cells are also explained. GDF8 and SERPINE1 expression in PCOS is given in detail.

Factors influencing the prevalence of polycystic ovary syndrome (PCOS) in the United Arab Emirates

Statistics indicate that at least 20-25% of women suffer from PCOS in the Gulf region. Despite its prevalence and negative implications on reproductive, metabolic, and physiological heath the exact cause of PCOS is unknown, in part due to the diversity of symptoms manifested by this disorder. In this review, we investigate causes of PCOS globally and draw on these studies, to determine the potential contributing factors for PCOS pathogenesis in the UAE population. The most frequently identified factors promoting PCOS pathogenesis that may be pertinent to this population include physiological factors such as insulin resistance, vitamin D deficiency, genetic factors, obesity, and anti-mullerian hormone (AMH) levels in the body as well as environmental factors such as air pollution, endocrine disrupting chemicals, and pesticide use. This evidence will help inform healthcare workers and government agencies to set up optimal guidelines for control and awareness of PCOS in the UAE.

Further delineation of familial polycystic ovary syndrome (PCOS) via whole-exome sequencing: PCOS-related rare FBN3 and FN1 gene variants are identified

AIM

To identify pathogenic rare coding Mendelian/high-effect size variant(s) by whole-exome sequencing in familial polycystic ovary syndrome (PCOS) patients to elucidate PCOS-related pathways.

METHODS

Twenty women and their affected available relatives diagnosed with PCOS according to Rotterdam criteria were recruited. Whole-exome sequencing on germ-line DNA from 31 PCOS probands and their affected relatives was performed. Whole-exome sequencing data were further evaluated by pathway and chemogenomics analyses. In-slico analysis of candidate variants were done by VarCards for functional predictions and VarSite for impact on three-dimensional (3D) structures in the candidate proteins.

RESULTS

Two heterozygous rare FBN3 missense variants in three patients, and one FN1 missense variant in one patient from three different PCOS families were identified.

CONCLUSION

We identified three novel FBN3 and FN1 variants for the first time in the literature and linked with PCOS. Further functional studies may identify causality of these newly discovered PCOS-related variants, and their role yet remains to be investigated. Our findings may improve our understanding of the biological pathways affected and identify new drug targets.

Pathophysiologic Mechanisms of Insulin Secretion and Signaling-Related Genes in Etiology of Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a common endocrinopathy in women. PCOS is characterized by anovulation, hyperandrogenism, polycystic ovaries, insulin resistance, and obesity. Despite the finding that the genetic origin of PCOS is well demonstrated in previous twin and familial clustering studies, genes and factors that can exactly explain the PCOS pathophysiology are not known. Objective(s). In this review, we attempted to identify genes related to secretion and signaling of insulin aspects of PCOS and their physiological functions in order to explain the pathways that are regulated by these genes which can be a prominent function in PCOS predisposition. Materials and Methods. For this purpose, published articles and reviews dealing with genetic evaluation of PCOS in women from peer-reviewed journals in PubMed and Google Scholar databases were included in this review. Results. The genomic investigations in women of different populations identified many candidate genes and loci that are associated with PCOS. The most important of them are INSR, IRS1-2, MTNR1A, MTNR1B, THADA, PPAR-γ2, ADIPOQ, and CAPN10. These are mainly associated with metabolic aspects of PCOS. Conclusions. In this review, we proposed that each of these genes may interrupt specific physiological pathways by affecting them and contribute to PCOS initiation. It is clear that the role of genes involved in insulin secretion and signaling is more critical than other pathways.

The role of polymorphism in various potential genes on polycystic ovary syndrome susceptibility and pathogenesis

Polycystic ovary syndrome (PCOS) is the most common endocrinopathies affecting the early reproductive age in women, whose pathophysiology perplexes many researchers till today. This syndrome is classically categorized by hyperandrogenism and/or hyperandrogenemia, menstrual and ovulatory dysfunction, bulky multi follicular ovaries on Ultrasonography (USG), and metabolic abnormalities such as hyperinsulinemia, dyslipidemia, obesity. The etiopathogenesis of PCOS is not fully elucidated, but it seems that the hypothalamus-pituitary-ovarian axis, ovarian, and/or adrenal androgen secretion may contribute to developing the syndrome. Infertility and poor reproductive health in women's lives are highly associated with elevated levels of androgens. Studies with ovarian theca cells taken from PCOS women have demonstrated increased androgen production due to augmented ovarian steroidogenesis attributed to mainly altered expression of critical enzymes (Cytochrome P450 enzymes: CYP17, CYP21, CYP19, CYP11A) in the steroid hormone biosynthesis pathway. Despite the heterogeneity of PCOS, candidate gene studies are the widely used technique to delineate the genetic variants and analyze for the correlation of androgen biosynthesis pathway and those affecting the secretion or action of insulin with PCOS etiology. Linkage and association studies have predicted the relationship between genetic variants and PCOS risk among families or populations. Several genes have been proposed as playing a role in the etiopathogenesis of PCOS, and the presence of mutations and/or polymorphisms has been discovered, which suggests that PCOS has a vital heritable component. The following review summarizes the influence of polymorphisms in crucial genes of the steroidogenesis pathway leading to intraovarian hyperandrogenism which can result in PCOS.

Polycystic Ovary Syndrome: the Epigenetics Behind the Disease

Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders, affecting approximately 5-20% of women of reproductive age. PCOS is a multifactorial, complex, and heterogeneous disease, characterized by hyperandrogenism, ovulatory dysfunction, and polycystic ovaries, which may lead to impaired fertility. Besides the reproductive outcomes, multiple comorbidities, such as metabolic disturbances, insulin resistance, obesity, diabetes, and cardiovascular disease, are associated with PCOS. In addition to the clear genetic basis, epigenetic alterations may also play a central role in PCOS outcomes, as environmental and hormonal alterations directly affect clinical manifestations and PCOS development. Here, we highlighted the epigenetic modifications in the multiplicity of clinical manifestations, as well as environmental epigenetic disruptors, as intrauterine hormonal and metabolic alterations affecting embryo development and the adulthood lifestyle, which may contribute to PCOS development. Additionally, we also discussed the new approaches for future studies and potential epigenetic biomarkers for the treatment of associated comorbidities and improvement in quality of life of women with PCOS.

Elevated maternal androgen is associated with dysfunctional placenta and lipid disorder in newborns of mothers with polycystic ovary syndrome

OBJECTIVE

To investigate the placental morphology alterations and identify the clinical characteristics of women with polycystic ovary syndrome (PCOS) and their newborns. Pregnant women with PCOS (n = 12) and pregnant women without PCOS (n = 11) were recruited. Then, the placenta, maternal blood and cord blood were collected after delivery.

DESIGN

Clinical observational study.

SETTING

Not applicable.

PATIENT(S)

In the present study, pregnant women with PCOS and healthy pregnant women were recruited from the clinic of the Department of Obstetrics and Gynecology, First Affiliated Hospital, Heilongjiang University of Chinese Medicine, China, between February 2015 and October 2015.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

A proteomic analysis was performed on the placenta in women with PCOS and healthy women.

RESULT(S)

The maternal testosterone, androstenedione, dehydroepiandrosterone sulfate, free androgen index, cholesterol, apolipoprotein B, and apolipoprotein B/apolipoprotein A-I levels were significantly higher in the PCOS group than in the control group, and the offspring in the PCOS group had higher dehydroepiandrosterone sulfate, high-density lipoprotein, and cholesterol levels, when compared with the control group. The placenta in the PCOS group demonstrated infarction, calcification, and a greater intervillous space, when compared with the control group. A higher level of estrogen receptor-β protein was observed in the placenta of women with PCOS, when compared with women without PCOS. A total of 258 proteins in the placenta were identified to be significantly different, when the PCOS and control groups were compared, and fibronectin 1 exhibited the closest relationship with other differential proteins.

CONCLUSION(S)

The overexposure to hyperandrogenism and hyperlipidemia affects the functions of the placenta, which are associated with the development of metabolic disorders in newborns.

Could insulin receptor H1085H C > T single nucleotide polymorphism predict insulin resistance in type 2 diabetic and chronic hepatitis C virus patients in Egypt?

Background

Insulin-receptor (INSR) is an α2β2 heterotetramer disulfide-linked trans-membrane glycoprotein and a family member of tyrosine kinase receptors. It mediates the pleiotropic actions of insulin regulating glucose homeostasis. It is encoded by a single gene: INSR gene. The INSR gene comprises 22 exons. Exons 17–22 encode the tyrosine kinase domain, and mutations in this region impair the function of the insulin receptor that may cause insulin resistance and hyperinsulinemia. Single nucleotide polymorphism with C > T substitution at His 1058 position of INSR (rs 1799817) located in exon 17 was considered to be involved in insulin resistance. Insulin receptor might be counter-regulated by degradation, differential expression, or modification by phosphorylation in cells expressing HCV core protein. HCV infection eventually leads to liver steatosis and fibrosis, increased oxidative stress, and peroxidation, all of which trigger a cascade of inflammatory responses, thus contributing to the development of insulin resistance. The present retrospective case-control aimed to study INSR H1085H C > T (rs 1799817) SNP in Egyptian patients suffering from chronic HCV infection with DM. The current study was conducted on two hundred and two participants of 100 males and 102 females, divided as follows: the control group (group I) included 50 apparently healthy volunteers of comparable age, sex, and socioeconomic status as patients groups, group II included 50 type 2 DM patients without HCV infection, group III included 52 chronic HCV infected patients without DM, and group IV included 50 HCV patients with DM.

Results

HOMA-IR and QUICKI index was significantly higher in the patient groups (groups II, III, and IV) than in controls (P < 0.001, P = 0.019, and P < 0.001, respectively). It was significantly lower in patients of group III than in patients of groups II and IV with P < 0.001 for both. DM patient group without HCV infection (group II) and HCV with DM (group IV) showed a significant decrease in CC genotypes and a significant increase in TT genotypes than the controls (P < 0.001, P = 0.018, respectively). HCV patients with DM (group IV) had the highest frequency of heterozygous genotype (CT) (50%). HCV-infected patients with T2DM (group IV) also showed a significantly higher frequency of minor allele (T) (35%) than controls (20%), and a lower frequency of the wild allele (C) (65%) than controls (80%).

Conclusion

The mutant allele “T” of INSR H1085H C > T (rs 1799817) SNP might be associated with an increased risk of developing insulin resistance and T2DM.

Recent advances in mammalian reproductive biology

Reproductive biology is a uniquely important topic since it is about germ cells, which are central for transmitting genetic information from generation to generation. In this review, we discuss recent advances in mammalian germ cell development, including preimplantation development, fetal germ cell development and postnatal development of oocytes and sperm. We also discuss the etiologies of female and male infertility and describe the emerging technologies for studying reproductive biology such as gene editing and single-cell technologies.

Pathophysiological mechanisms of gonadotropins- and steroid hormones-related genes in etiology of polycystic ovary syndrome

OBJECTIVES

Polycystic ovary syndrome (PCOS) is an endocrinopathy in women, which, unlike its impact on fertility and health of women, there is no clear understanding about the causal mechanisms of this pathogenesis. The aim of this review paper is to investigate the pathophysiological pathways affecting the PCOS etiology, based on functions of gonadotropins- and steroid hormones-related genes.

MATERIALS AND METHODS

Due to different hormonal and metabolic signs of this complex disorder, different hypotheses are mentioned about etiology of this syndrome. Because of the heterogeneity of the reasons given for this syndrome and the spread of the effective genes in its pathophysiology, most of genes affected by sex-related hormonal imbalances are examined for discriminative diagnosis. For this purpose, published articles and reviews dealing with genetic evaluation of PCOS in women in peer-reviewed journals in PubMed and Google Scholar databases were included in this review.

RESULTS

In previous studies, it has been well demonstrated that PCOS in some individuals have a genetic origin. Pathophysiological functions of genes are primarily responsible for the synthesis of proteins that have role in PCOS before hyperandrogenism including GnRHR, FSHβ, FSHR, LHCGR, CYP19A1, HSD17B, AR and SHBG, and their effects in PCOS of human have been confirmed.

CONCLUSION

Hormonal imbalances are the first reason mentioned in PCOS etiology, and usually characterized with menstrual irregularities in PCOS women. Hyperandrogenism and gonadotropin secretion disorders are shown in PCOS condition, which are related to steroidogenesis pathways and hypothalamic-pituitary-ovarian axis disturbances, respectively.

Vitamin D receptor polymorphisms and the polycystic ovary syndrome: A systematic review

Polycystic ovary syndrome (PCOS) is the most frequent endocrinological disorder that affects women of reproductive age, leading to metabolic alterations, such as hyperandrogenism, obesity, menstrual irregularities, insulin resistance, and polycystic ovaries. The etiology remains unclear, but several genetic and environmental factors have been correlated with manifestations of this syndrome. Vitamin D plays important roles in metabolic pathways affected by PCOS, including calcium homeostasis, the insulin pathway, and sex hormone synthesis. Vitamin D concentration has been related with the severity of this disorder, and vitamin D receptor polymorphisms have been shown in some studies to have an association with some of the patterns presented by PCOS. The objective of this study is to provide an up-to-date review about vitamin D receptor polymorphisms and their association with PCOS.

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.

Perspectives in Polycystic Ovary Syndrome: From Hair to Eternity

CONTEXT

Polycystic ovary syndrome (PCOS) is a common complex genetic disease. It is characterized by hyperandrogenism, gonadotropin secretory changes, polycystic ovarian morphology, and insulin resistance. The etiology of PCOS remains unknown, but modern genetic approaches, such as genome-wide association studies (GWAS), Mendelian randomization, and next-generation sequencing, promise to identify the pathways that are primarily disrupted.

EVIDENCE ACQUISITION

The literature on PCOS, including the author's research, is discussed.

EVIDENCE SYNTHESIS

Recent genetic analyses are reviewed.

CONCLUSIONS

Considerable progress has been made mapping PCOS susceptibility genes. GWAS have implicated gonadotropin secretion and action as important primary defects in disease pathogenesis in European and Han Chinese PCOS cohorts, respectively. European women with the National Institutes of Health and Rotterdam phenotypes as well as those with self-reported PCOS have some gene regions in common, such as chromosome 11p14.1 region containing the FSH B polypeptide (FSHB) gene, suggesting shared genetic susceptibility. Several chromosomal signals are significant in both Han Chinese and European PCOS cohorts, suggesting that the susceptibility genes in these regions are evolutionarily conserved. In addition, GWAS have suggested that DENND1A, epidermal growth factor signaling, and DNA repair pathways play a role in PCOS pathogenesis. Only a small amount of the heritability of PCOS is accounted for by the common susceptibility variants mapped so far. Future studies should clarify the contribution of rare genetic variants and epigenetic factors to the PCOS phenotype. Furthermore, Mendelian randomization can be used to clarify causal relationships, and phenome-wide association studies can provide insight into health risks associated with PCOS susceptibility variants.

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.

•

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

•

We discovered associations between mitogenic signaling components and phenotypes.

Functional genomics of PCOS: from GWAS to molecular mechanisms

Polycystic ovary syndrome (PCOS) is a common endocrinopathy characterized by increased ovarian androgen biosynthesis, anovulation, and infertility. PCOS has a strong heritable component based on familial clustering and twin studies. Genome-wide association studies (GWAS) identified several PCOS candidate loci including LHCGR, FSHR, ZNF217, YAP1, INSR, RAB5B, and C9orf3. We review the functional roles of strong PCOS candidate loci focusing on FSHR, LHCGR, INSR, and DENND1A. We propose that these candidates comprise a hierarchical signaling network by which DENND1A, LHCGR, INSR, RAB5B, adapter proteins, and associated downstream signaling cascades converge to regulate theca cell androgen biosynthesis. Future elucidation of the functional gene networks predicted by the PCOS GWAS will result in new diagnostic and therapeutic approaches for women with PCOS.

An exon variant in insulin receptor gene is associated with susceptibility to colorectal cancer in women

Given the role of insulin resistance in colorectal cancer (CRC), we explored whether genetic variants in insulin (INS), insulin receptor (INSR), insulin receptor substrate 1 (IRS1), insulin receptor substrate 2 (IRS2), insulin-like growth factor 1 (IGF1), and insulin-like growth factor binding protein 3 (IGFBP3) genes were associated with CRC risk. A total of 600 subjects, including 261 cases with CRC and 339 controls, were enrolled in this case-control study. Six polymorphisms in INS (rs689), INSR (rs1799817), IRS1 (rs1801278), IRS2 (rs1805097), IGF1 (rs5742612), and IGFBP3 (rs2854744) genes were genotyped using PCR-RFLP method. No significant difference was observed for INS, INSR, IRS1, IRS2, IGF1, and IGFBP3 genes between the cases and controls. However, the INSR rs1799817 "TT + CT" genotype and "CT" genotype compared with "CC" genotype occurred more frequently in the women with CRC than women controls (P = 0.007; OR = 1.93, 95 %CI = 1.20-3.11 and P = 0.002, OR = 2.15, 95 %CI = 1.31-3.53, respectively), and the difference remained significant after adjustment for confounding factors including age, BMI, smoking status, NSAID use, and family history of CRC (P = 0.018; OR = 1.86, 95 %CI = 1.11-3.10 and P = 0.004, OR = 2.18, 95 %CI = 1.28-3.71, respectively). In conclusion, to our knowledge, this study indicated for the first time that the INSR rs1799817 TT + CT genotype and CT genotype compared with the CC genotype had 1.86-fold and 2.18-fold increased risks for CRC among women, respectively. Furthermore, this finding is in line with previous studies which found significant associations between other variants of the INSR gene and CRC risk. Nevertheless, further studies are required to confirm our findings.

Prevalence and clinical profile of insulin resistance in young women of poly cystic ovary syndrome: A study from Pakistan

Objective: The aim was to estimate the prevalence of Insulin Resistance (IR) in Poly Cystic Ovary Syndrome (PCOS) and analyze its clinical parameters.

Methodology: This observational study was conducted at Dow University Hospital during June 2011 till May 2012. Patients of PCOS were selected, an anthropometric measurement, examination and fasting blood test for sugar (FBS) and insulin was performed. Data was collected on pre designed questionnaire, was analyzed by SPSS version 16.

Results: Forty-six cases of PCOS were included in the study. Prevalence of IR was 34.78%. Mean age of patients was 23.72 ± 4.37 years. Waist Hip Ratio (WHR) was raised in 42 (91.30%), acanthosis was found in 26(56.50%), impaired FBS was seen in 9 (19.6%) and raised fasting insulin in 16 (34.8%) patients. There was significant association between acanthosis and WHR (0.044) and between acanthosis and FBS (0.008). Correlation studies between parameters showed a significant correlation between Waist & Hips (0.93), similarly Waist & WHR showed positive correlation (0.59), at p< 0.01. Significant positive correlation was also found between waist and FBS (0.32) and FBS & WHR (0.378).

Conclusion: Acanthosis nigrican, raised WHR and FBS are significant parameters for insulin resistance in cases of Poly Cystic Ovary Syndrome (PCOS).

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.

SGTA: a new player in the molecular co-chaperone game

Small glutamine-rich tetratricopeptide repeat-containing protein α (SGTA) is a steroid receptor molecular co-chaperone that may substantially influence hormone action and, consequently, hormone-mediated carcinogenesis. To date, published studies describe SGTA as a protein that is potentially critical in a range of biological processes, including viral infection, cell division, mitosis, and cell cycle checkpoint activation. SGTA interacts with the molecular chaperones, heat shock protein 70 (HSP70) and HSP90, and with steroid receptor complexes, including those containing the androgen receptor. Steroid receptors are critical for maintaining cell growth and differentiation in hormonally regulated tissues, such as male and female reproductive tissues, and also play a role in disease states involving these tissues. There is growing evidence that, through its interactions with chaperones and steroid receptors, SGTA may be a key player in the pathogenesis of hormonally influenced disease states, including prostate cancer and polycystic ovary syndrome. Research into the function of SGTA has been conducted in several model organisms and cell types, with these studies showing that SGTA functionality is cell-specific and tissue-specific. However, very few studies have been replicated in multiple cell types or experimental systems. Although a broad range of functions have been attributed to SGTA, there is a serious lack of mechanistic information to describe how SGTA acts. In this review, published evidence linking SGTA with hormonally regulated disease states is summarized and discussed, highlighting the need for future research to more clearly define the biological function(s) of this potentially important co-chaperone.

Genetic variants associated with insulin signaling and glucose homeostasis in the pathogenesis of insulin resistance in polycystic ovary syndrome: a systematic review

BACKGROUND

Polycystic ovary syndrome must be recognized as a serious issue due to its implication on long term health regardless of an individual's age. PCOS and insulin resistance are interlinked, as approximately 40 % of women with PCOS are insulin resistant. However, the detailed molecular basis for insulin resistance that is coupled with PCOS remains poorly understood.

OBJECTIVE

To review the published evidence that polymorphisms in genes that are involved in insulin secretion and action are associated with an increased risk of PCOS.

METHODS

We reviewed articles published through November 2012 which concerned polymorphisms of genes related to insulin signaling and glucose homeostasis as well as their associations with PCOS. The articles were identified via Medline searches.

CONCLUSIONS

No consistent evidence emerged of a strong association between the risk of PCOS and any known gene that is related to insulin signaling and glucose homeostasis. Moreover, recent genome-wide association studies are inconsistent in identifying the associations between PCOS and insulin metabolism genes. Many of the studies reviewed were limited by heterogeneity in the PCOS diagnosis and by not have having a sufficient number of study participants. Further studies are warranted to determine predisposing risk factors which could modify environmental factors and thus reduce the risk of PCOS. Large genome-wide association studies devoted solely to PCOS will be necessary to identify new candidate genes and proteins that are involved in PCOS risk.

The role of TGF-β in polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a common endocrine disorder characterized by chronic oligoanovulation and hyperandrogenism and associated with insulin resistance, type 2 diabetes, and cardiovascular risk. In recent years, genetic studies have linked PCOS to a dinucleotide marker D19S884 in the fibrillin 3 gene. Fibrillins make up the major component of microfibrils in the extracellular matrix (ECM) and interact with molecules in the ECM to regulate transforming growth factor β (TGF-β) signaling. Therefore, variations in fibrillin 3 and subsequent dysregulation of TGF-β may contribute to the pathogenesis of PCOS. Here, we review the evidence from genetic studies supporting the role of TGF-β in PCOS and describe how TGF-β dysregulation may contribute to (1) the fetal origins of PCOS, (2) reproductive abnormalities in PCOS, and (3) cardiovascular and metabolic abnormalities in PCOS.

Small glutamine-rich tetratricopeptide repeat-containing protein alpha is present in human ovaries but may not be differentially expressed in relation to polycystic ovary syndrome

OBJECTIVE

To evaluate the expression and function of small glutamine-rich tetratricopeptide repeat-containing protein alpha (SGTA), an androgen receptor (AR) molecular chaperone, in human ovarian tissues.

DESIGN

Examine the effect of SGTA on AR subcellular localization in granulosa tumor cells (KGN) and SGTA expression in ovarian tissues.

SETTING

University-based research laboratory.

PATIENT(S)

Archived tissues from premenopausal women and granulosa cells from infertile women receiving assisted reproduction.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

AR subcellular localization and SGTA protein or mRNA levels.

RESULT(S)

SGTA and AR proteins were expressed in the cytoplasm of KGN cells and exposure to androgen stimulated AR nuclear localization. SGTA protein knockdown increased AR nuclear localization at low (0-0.1 nmol/L) but not high (1-10 nmol/L) concentrations of androgen hormone. In ovarian tissues, SGTA was localized to the cytoplasm of granulosa cells at all stages of folliculogenesis and in thecal cells of antral follicles. SGTA protein levels were similar when comparing primordial and primary follicles within core biopsies (n = 40) from women with and without polycystic ovary syndrome (PCOS). Likewise, SGTA mRNA levels were not significantly different in granulosa cells from preovulatory follicles after hyperstimulation of women with and without PCOS.

CONCLUSION(S)

SGTA is present in human ovaries and has the potential to modulate AR signalling, but it may not be differentially expressed in PCOS.

Insulin resistance and the polycystic ovary syndrome revisited: an update on mechanisms and implications

Polycystic ovary syndrome (PCOS) is now recognized as an important metabolic as well as reproductive disorder conferring substantially increased risk for type 2 diabetes. Affected women have marked insulin resistance, independent of obesity. This article summarizes the state of the science since we last reviewed the field in the Endocrine Reviews in 1997. There is general agreement that obese women with PCOS are insulin resistant, but some groups of lean affected women may have normal insulin sensitivity. There is a post-binding defect in receptor signaling likely due to increased receptor and insulin receptor substrate-1 serine phosphorylation that selectively affects metabolic but not mitogenic pathways in classic insulin target tissues and in the ovary. Constitutive activation of serine kinases in the MAPK-ERK pathway may contribute to resistance to insulin's metabolic actions in skeletal muscle. Insulin functions as a co-gonadotropin through its cognate receptor to modulate ovarian steroidogenesis. Genetic disruption of insulin signaling in the brain has indicated that this pathway is important for ovulation and body weight regulation. These insights have been directly translated into a novel therapy for PCOS with insulin-sensitizing drugs. Furthermore, androgens contribute to insulin resistance in PCOS. PCOS may also have developmental origins due to androgen exposure at critical periods or to intrauterine growth restriction. PCOS is a complex genetic disease, and first-degree relatives have reproductive and metabolic phenotypes. Several PCOS genetic susceptibility loci have been mapped and replicated. Some of the same susceptibility genes contribute to disease risk in Chinese and European PCOS populations, suggesting that PCOS is an ancient trait.

Fibrillin-3 in the fetal ovary: can it contribute to polycystic ovary syndrome?

Evaluation of: Hatzirodos N, Bayne RA, Irving-Rodgers HF et al. Linkage of regulators of TGF-β activity in the fetal ovary to polycystic ovary syndrome. FASEB J. 25(7), 2256-2265 (2011). Polycystic ovary syndrome (PCOS), a prevalent hyperandrogenic and anovulatory infertility and metabolic syndrome in reproductive-aged women, is heritable but its etiology is unknown. An allele within an intron of fibrillin-3, a TGF-β pathway regulator, is reliably associated with PCOS, and the epigenome of an early gestation monkey model for PCOS implicates altered TGF-β signaling. In the recent article by Hatzirodos et al., and in contrast to prior findings in mature human ovaries, prominent and transient fibrillin-3 expression is found in human and bovine fetal ovarian stroma during early gestation. Such developmentally constrained ovarian expression of a gene associated with PCOS phenotype has considerable implications for fetal origins of PCOS in women. Further study is needed, however, to determine whether differential expression of fetal ovarian fibrillin-3 results in polycystic ovary morphology, and whether differential fetal expression of fibrillin-3 in non-ovarian tissues enables PCOS-like dysfunction.

Contemporary genetic technologies and female reproduction

BACKGROUND

The Fifth Evian Annual Reproduction (EVAR) Workshop Meeting discussed knowledge regarding contemporary genetics in female reproduction.

METHODS

Specialist reproductive medicine clinicians and geneticists delivered presentations based on published literature and current research. The content of this report is based on the expert presentations and subsequent group discussions that took place during this Workshop.

RESULTS

Numerous ovarian genes with a role in infertility have been identified. Future challenges for genetic screening of patients, such as those with polycystic ovary syndrome, primary ovarian insufficiency or endometriosis, include the identification of high-throughput strategies and how to apply these findings to infertile patients. The identification of high-quality embryos in IVF using objective technologies remains a high priority in order to facilitate single-embryo transfer. Gene expression profiling of cumulus cells surrounding the oocyte, and proteomic and metabolomic approaches in embryo culture media may significantly improve non-invasive embryo quality assessment.

CONCLUSIONS

The way forward in advancing the knowledge of genes involved in reproduction was considered to be through genome-wide association studies involving large numbers of patients. Establishing international collaboration is required to enable the application of such technologies in sufficient numbers of patients.

Understanding polycystic ovarian syndrome pathogenesis: an updated of its genetic aspects

Polycystic ovary syndrome (PCOS) is the most frequent cause of female infertility. It is also characterized by metabolic defects that raise the risk for cardiovascular disease. Despite the progress in the definition of the clinical aspects of the syndrome, only very few definite data are available about the ethiopathogenetic mechanisms that subtend PCOS. It is likely that the PCOS phenotype derives from the interaction between environmental and genetic factors. While environmental factors have easily been investigated, the individuation of the genetic factors seem to be more complex. Indeed, PCOS appears to be inherited as a complex, polygenic trait. Several family studies have been conducted with the aim to clarify the genetic aspects of PCOS, but their findings are often conflicting and not conclusive.Moreover, it is difficult to establish with certainty which genes are involved and their effective role in the development of the syndrome because in PCOS, genetic analysis is hampered by low fecundity, lack of a male phenotype, absence of an animal model, and dissimilarity of the diagnostic criteria used to select the patients. Since multiple biochemical pathways are implicated in PCOS pathogenesis, genes of steroid hormone metabolism, gonadotropin release and action, insulin secretion and action, adipose tissue metabolism and others have been investigated. Nevertheless, none of them seems to play a key role in the ethiopathogenesis of PCOS. This article reviews the large body of literature generated to support the presence of genetic abnormalities in PCOS women by taking in consideration the most important studies regarding PCOS candidate genes.

The Genetic Basis of the Polycystic Ovary Syndrome: A Literature Review Including Discussion of PPAR-gamma

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder of the women of reproductive age. Familial clustering of PCOS has been consistently reported suggesting that genetic factors play a role in the development of the syndrome although PCOS cases do not exhibit a clear pattern of Mendelian inheritance. It is now well established that PCOS represents a complex trait similar to type-2 diabetes and obesity, and that both inherited and environmental factors contribute to the PCOS pathogenesis. A large number of functional candidate genes have been tested for association or linkage with PCOS phenotypes with more negative than positive findings. Lack of universally accepted diagnostic criteria, difficulties in the assignment of male phenotype, obscurity in the mode of inheritance, and particularly small sample size of the study populations appear to be major limitations for the genetic studies of PCOS. In the near future, utilizing the genome-wide scan approach and the HapMap project will provide a stronger potential for the genetic analysis of the syndrome.

Polycystic ovary syndrome in the pediatric population

Polycystic ovary syndrome (PCOS) is a common disorder characterized by hyperandrogenism and disordered gonadotropin secretion, often associated with insulin resistance. The syndrome, which modulates both hormonal and metabolic processes, is the most common endocrinopathy in reproductive-age women and increases a woman's risk of infertility, endometrial pathology, and cardiometabolic disease. As it is currently defined, PCOS most likely encompasses several distinct diseases with similar clinical phenotypes but different underlying pathophysiological processes. However, hyperandrogenism remains the syndrome's clinical hallmark. The clinical manifestations of PCOS often emerge during childhood or in the peripubertal years, suggesting that the syndrome is influenced by fetal programming and/or early postnatal events. However, given that the full clinical spectrum of PCOS does not typically appear until puberty, a "two-hit" hypothesis has been proposed: (1) a girl develops hyperandrogenism via one or more of many different potential mechanisms; (2) the preexisting hyperandrogenism subsequently disturbs the hypothalamic–pituitary–ovarian axis, resulting in ovulatory dysfunction and sustained hyperandrogenism. No consensus guidelines exist regarding the diagnosis and management of PCOS in the pediatric population; however, because the syndrome is a diagnosis of exclusion, the clinical evaluation of girls suspected of having PCOS is aimed at excluding other causes of androgen excess and menstrual dysfunction. For the syndrome's management, emphasis is placed on lifestyle and symptom-directed treatment.

A variant in the fibrillin-3 gene is associated with TGF-β and inhibin B levels in women with polycystic ovary syndrome

In an attempt to evaluate the association between allele 8 (A8) of D19S884 in the fibrillin-3 gene and circulating transforming growth factor (TGF) β and inhibin levels in women with polycystic ovary syndrome (PCOS), we studied 120 similarly aged women from families with PCOS and compared 40 women with PCOS who did not have A8 (A8- PCOS) with 40 women with PCOS who had A8 (A8+ PCOS) and 40 normally menstruating women who did not have either PCOS or A8 (A8- Non-PCOS). A8- PCOS is associated with higher levels of TGF-β1 compared with A8+ PCOS or A8- Non-PCOS, similar levels of TGF-β2 compared with A8+ PCOS but lower levels of TGF-β2 compared with A8- Non-PCOS, and lower levels of inhibin B and aldosterone compared with A8+ PCOS.

Genetic basis of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is associated with obesity and manifests with reproductive, hyperandrogenic and metabolic features. Although the etiology of PCOS is complex and incompletely understood, genetics plays an important role (heritability: ∼70%). Potential problems with studying the genetics of PCOS include the heterogeneity of the condition and associated sub-fertility. A candidate gene approach has been used in over 70 published studies on PCOS, most of which have been inadequately powered to detect a statistically meaningful association. Furthermore, these studies often fail to replicate prior published studies on the same candidate gene in different populations. The first genome-sequence variant (identified from a genome-wide association study in subjects with Type 2 diabetes mellitus) to be studied in PCOS (FTO gene) has been shown by our group to associate with susceptibility for the development of PCOS. This is the first genetic corroboration of a link between PCOS and obesity. Future directions include a genome-wide association study in PCOS.

The role of the polycystic ovary syndrome susceptibility locus D19S884 allele 8 in maternal glycemia and fetal size

CONTEXT

The high incidence of insulin resistance, type 2 diabetes, and metabolic syndrome in Western societies and their impact on quality of life emphasize the importance of identifying underlying susceptibility loci for metabolic diseases. The polycystic ovary syndrome (PCOS) susceptibility locus D19S884 allele 8 (A8) is associated with measures of insulin resistance, beta-cell dysfunction, and other metabolic phenotypes in PCOS families. We now investigate the role of D19S884 A8 in pregnancy.

OBJECTIVE

Using the multiethnic Hyperglycemia and Adverse Pregnancy Outcome cohort, we assessed the associations of D19S884 A8 with measures of maternal glycemia and fetal size.

DESIGN

We tested for association of maternal D19S884 A8 with maternal outcomes (fasting, 1-h, and 2-h plasma glucose, and fasting and 1-h C-peptide from an oral glucose tolerance test) and fetal and maternal D19S884 A8 with fetal outcomes (birth weight, length, head circumference, sum of skin folds, fat mass, cord C-peptide, and 2-h neonatal plasma glucose).

SUBJECTS

We analyzed 4424 Caucasian mothers and 3347 offspring of northern European ancestry, 1957 Thai mothers and 2089 offspring from Bangkok, 1208 Afro-Caribbean mothers and 1209 offspring from Barbados, and 774 Hispanic mothers and 762 offspring from Bellflower, California.

RESULTS

After adjusting for confounding variables and multiple testing, neither maternal nor fetal D19S884 A8 showed significant evidence for association with any of the outcomes tested.

CONCLUSIONS

The PCOS susceptibility locus, D19S884 A8, is not a major factor contributing to glycemia during pregnancy or fetal size in a general obstetric population.

Family-based analysis of candidate genes for polycystic ovary syndrome

CONTEXT

Polycystic ovary syndrome (PCOS) is a complex disorder having both genetic and environmental components. A number of association studies based on candidate genes have reported significant association, but few have been replicated. D19S884, a polymorphic marker in fibrillin 3 (FBN3), is one of the few association findings that has been replicated in independent sets of families.

OBJECTIVE

The aims of the study are: 1) to genotype single nucleotide polymorphisms (SNPs) in the region of D19S884; and 2) to follow up with an independent data set, published results reporting evidence for PCOS candidate gene associations.

DESIGN

The transmission disequilibrium test (TDT) was used to analyze linkage and association between PCOS and SNPs in candidate genes previously reported by us and by others as significantly associated with PCOS.

SETTING

The study was conducted at academic medical centers.

PATIENTS OR OTHER PARTICIPANTS

A total of 453 families having a proband with PCOS participated in the study. Sisters with PCOS were also included. There was a total of 502 probands and sisters with PCOS.

INTERVENTION(S)

There were no interventions.

MAIN OUTCOME MEASURE(S)

The outcome measure was transmission frequency of SNP alleles.

RESULTS

We identified a six-SNP haplotype block spanning a 6.7-kb region on chromosome 19p13.2 that includes D19S884. SNP haplotype allele-C alone and in combination with D19S884-allele 8 is significantly associated with PCOS: haplotype-C TDT chi(2) = 10.0 (P = 0.0016) and haplotype-C/A8 TDT chi(2) = 7.6 (P = 0.006). SNPs in four of the other 26 putative candidate genes that were tested using the TDT were nominally significant (ACVR2A, POMC, FEM1B, and SGTA). One SNP in POMC (rs12473543, chi(2) = 9.1; P(corrected) = 0.042) is significant after correction for multiple testing.

CONCLUSIONS

A polymorphic variant, D19S884, in FBN3 is associated with risk of PCOS. POMC is also a candidate gene of interest.

Genetic and gene expression analyses of the polycystic ovary syndrome candidate gene fibrillin-3 and other fibrillin family members in human ovaries

Several studies have demonstrated an association between polycystic ovary syndrome (PCOS) and the dinucleotide repeat microsatellite marker D19S884, which is located in intron 55 of the fibrillin-3 (FBN3) gene. Fibrillins, including FBN1 and 2, interact with latent transforming growth factor (TGF)-β-binding proteins (LTBP) and thereby control the bioactivity of TGFβs. TGFβs stimulate fibroblast replication and collagen production. The PCOS ovarian phenotype includes increased stromal collagen and expansion of the ovarian cortex, features feasibly influenced by abnormal fibrillin expression. To examine a possible role of fibrillins in PCOS, particularly FBN3, we undertook tagging and functional single nucleotide polymorphism (SNP) analysis (32 SNPs including 10 that generate non-synonymous amino acid changes) using DNA from 173 PCOS patients and 194 controls. No SNP showed a significant association with PCOS and alleles of most SNPs showed almost identical population frequencies between PCOS and control subjects. No significant differences were observed for microsatellite D19S884. In human PCO stroma/cortex (n = 4) and non-PCO ovarian stroma (n = 9), follicles (n = 3) and corpora lutea (n = 3) and in human ovarian cancer cell lines (KGN, SKOV-3, OVCAR-3, OVCAR-5), FBN1 mRNA levels were approximately 100 times greater than FBN2 and 200–1000-fold greater than FBN3. Expression of LTBP-1 mRNA was 3-fold greater than LTBP-2. We conclude that FBN3 appears to have little involvement in PCOS but cannot rule out that other markers in the region of chromosome 19p13.2 are associated with PCOS or that FBN3 expression occurs in other organs and that this may be influencing the PCOS phenotype.

FEM1A and FEM1B: novel candidate genes for polycystic ovary syndrome

BACKGROUND

Human homologs (FEM1A, FEM1B, FEM1C) of nematode sex determination genes are candidate genes for polycystic ovary syndrome (PCOS). We previously identified a FEM1A mutation (H500Y) in a woman with PCOS; FEM1B has been implicated in insulin secretion.

METHODS

Women with and without PCOS (287 cases, 187 controls) were genotyped for H500Y and six FEM1A single nucleotide polymorphisms (SNPs), five FEM1B SNPs and five FEM1C SNPs. SNPs and haplotypes were determined and tested for association with PCOS and component phenotypes.

RESULTS

No subject carried the FEM1A H500Y mutation. FEM1A SNPs rs8111933 (P = 0.001) and rs12460989 (P = 0.046) were associated with an increased likelihood of PCOS whereas FEM1A SNP rs1044386 was associated with a reduced probability of PCOS (P = 0.013). FEM1B SNP rs10152450 and a linked SNP were associated with a reduced likelihood of PCOS (P = 0.005), and lower homeostasis model assessment (HOMA) for beta-cell function (HOMA-%B, P = 0.011) and lower HOMA for insulin resistance (HOMA-IR, P = 0.018). FEM1B SNP rs12909277 was associated with lower HOMA-%B (P = 0.008) and lower HOMA-IR (P = 0.037). Haplotype associations were consistent with SNP results, and also revealed association of FEM1B haplotype TGAGG with increased HOMA-%B (P = 0.007) and HOMA-IR (P = 0.024). FEM1C variants were not associated with PCOS.

CONCLUSIONS

This study presents evidence suggesting a role for FEM1A and FEM1B in the pathogenesis of PCOS. Only FEM1B variants were associated with insulin-related traits in PCOS women, consistent with prior evidence linking this gene to insulin secretion. Replication of these associations and mechanistic studies will be necessary to establish the role of these genes in PCOS.

Polycystic ovary syndrome in adolescents

BACKGROUND

Polycystic ovary syndrome (PCOS) is the commonest endocrine disorder in women and typically presents during adolescence. The clinical and biochemical presentation is heterogeneous, but elevated serum concentrations of androgens are the most consistent biochemical abnormality and may be considered to be the hallmark of the syndrome. Many women with PCOS also have insulin resistance and hyperinsulinaemia, which may contribute to the clinical and endocrine abnormalities. The aetiology of PCOS is not clear but studies in the Rhesus monkey suggest that exposure to excess androgen during intrauterine life results in many of the features of human PCOS, including ovarian dysfunction, abnormal LH secretion and insulin resistance.

OBJECTIVE

To review the studies from the literature, including those of the author, regarding aetiology, presentation and management of PCOS in adolescents.

RESULTS AND CONCLUSIONS

We have proposed that PCOS in adolescents arises as a result of a genetically determined disorder of ovarian function that results in hyper-secretion of androgens, possibly during fetal life and also during physiological activation of the hypothalamic-pituitary-ovarian in infancy and at the onset of puberty. There is plentiful evidence for a genetic basis for PCOS (it appears to be a complex endocrine disorder resulting from the effects of a several genes), but environmental factors, notably nutrition, influence the clinical and biochemical phenotype. Obesity unmasks or amplifies symptoms, endocrine and metabolic abnormalities. The increasing incidence of childhood obesity has resulted in an alarming Increase not only in distressing symptoms but also impaired glucose tolerance and even diabetes among adolescent girls with PCOS. The search for PCOS genes in this condition, that is not only heterogeneous but also presents only in women of reproductive age, is not straightforward and has produced few convincing candidates so far. In due course, however, identification of the major susceptibility loci is likely to provide key insight into the aetiology of the syndrome and improve diagnosis and management.

A novel single nucleotide polymorphism of INSR gene for polycystic ovary syndrome

OBJECTIVE

To investigate several single nucleotide polymorphisms (SNPs) in the insulin receptor (INSR) gene that have significant associations with pathogenesis of polycystic ovary syndrome (PCOS) in a Korean population.

DESIGN

Case-control study.

SETTING

University-based hospital.

PATIENT(S)

134 patients with PCOS and 100 healthy women as controls.

INTERVENTION(S)

All exons of INSR in DNA samples from 100 healthy women and 134 women with PCOS were sequenced and compared.

MAIN OUTCOME MEASURE(S)

Frequencies of genotypes for several SNPs in INSR gene that were found as specifically expressed SNPs in a Korean population.

RESULT(S)

Among nine SNPs analyzed in a large population, the genotypic frequencies of eight SNPs were similar, and they had no statistically significant association with PCOS. However, the frequency of a minor allele for one novel SNP, +176477 C>T, was higher in the control group than the patient group.

CONCLUSION(S)

Among the analyzed SNPs, +176477 C>T, a novel SNP in the INSR gene, was associated with the pathogenesis of PCOS in a Korean population.

Small glutamine-rich tetratricopeptide repeat-containing protein alpha (SGTA), a candidate gene for polycystic ovary syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS) is a heterogenic, complex common genetic disease. Multiple pathways are involved in its pathogenesis, including the androgen signaling pathway and insulin signaling pathway. Small glutamine-rich tetratricopeptide repeat-containing protein alpha (SGTA) is a putative member of the androgen receptor-chaperone-co-chaperone complex, and may play a role in androgen signaling as a co-chaperone. Polymorphisms in the SGTA gene have not been evaluated for a role in PCOS.

METHODS

Women with and without PCOS (287 cases, 187 controls) were genotyped for three single nucleotide polymorphisms (SNPs) in SGTA. SNPs and haplotypes were determined and tested for association with PCOS and component traits of PCOS.

RESULTS

For SNP rs1640262, homozygotes for the minor allele were protected against PCOS (P = 0.009). Haplotype 1 (G-A-T) was associated with increased risk of PCOS (P = 0.015). In women with PCOS, haplotype 2 (A-G-C) was associated with increased insulin resistance (P = 0.013), consequently resulting in increased insulin secretion (P = 0.014).

CONCLUSIONS

This study presents genetic evidence suggesting a potential role of SGTA in the pathogenesis of PCOS. SGTA may provide a connection between multiple pathways in PCOS.

Genetic approaches to polycystic ovarian syndrome

PURPOSE OF REVIEW

This review clarifies the challenges facing investigators in the search for polycystic ovarian syndrome candidate genes.

RECENT FINDINGS

Evidence for fibillin 3 has emerged as a polycystic ovarian syndrome candidate gene. The sex hormone binding gene also shows promise, as does evidence for fetal programming and X-chromosome inactivation.

SUMMARY

As with many complex disorders, the heritability of polycystic ovarian syndrome has eluded investigators. Although familial aggregation studies have demonstrated clearly a genetic component to the syndrome, simple Mendelian models do not characterize its mode of inheritance. Instead, multiple loci and epigenetic modification may play a role in the phenotype. The candidate gene approach relies upon improved statistical and technological methods to analyze potential genes based on biologic plausibility. Pathways that affect steroidogenesis, insulin resistance, gonadotropin function, and obesity provide potential genes for investigation. Obstacles such as phenotypic variability, lack of a male phenotype, multiple attempts at analysis, and small sample sizes hamper these efforts. Nevertheless, great care must be taken to apply rigorous standards as we proceed with genetic studies. In addition to increasing our knowledge of common disorders, potential benefits include personalized medicine, with pharmacogenetics allowing therapies tailored to the individual.

Polycystic ovary syndrome: a focus on anti-Müllerian hormone levels

Anti-Müllerian hormone (AMH) is a dimeric glycoprotein exclusively produced by the granulosa cells and reflects the size of the growing follicular pool. Serum AMH levels seem to correlate with the development of preantral and small-antral follicles during reproductive life. It has been established that AMH levels are two- to threefold higher in adult women with polycystic ovary syndrome (PCOS) compared with healthy women. This may be related to an increased number of growing follicles that secrete AMH or to an increased per granulosa cell production. Therefore, the understanding of its regulation is important to advance the comprehension of PCOS pathophysiology. Apparently, androgens may play an important role in this regard. Recently, our group documented higher serum levels of AMH in daughters of women with PCOS compared with control girls during three stages of sexual development, early infancy, childhood and peripuberty, suggesting the presence of an increased growing follicular pool in these girls that is established early in development and precedes the onset of clinical hyperandrogenism. In addition, clinical and experimental studies suggest that androgens could also have a role in determining an increased follicular mass during prenatal life, which, during postnatal life, may perpetuate hyperandrogenism. Currently, AMH determination is being progressively used in clinical practice as a marker of ovarian function. In the future, it may become a useful tool to assess ovarian aging and reserve, to diagnose PCOS and to evaluate treatment success.

Identification of a polycystic ovary syndrome susceptibility variant in fibrillin-3 and association with a metabolic phenotype

CONTEXT

Polycystic ovary syndrome (PCOS), the most common reproductive endocrine disorder of premenopausal women, is also associated with metabolic abnormalities including insulin resistance and an increased risk for diabetes mellitus. We previously mapped a PCOS susceptibility locus to chromosome 19p13.2 near the dinucleotide repeat marker D19S884.

OBJECTIVE

Our objective is to localize the chromosome 19p13.2 PCOS susceptibility locus and determine its impact on metabolic features of PCOS.

DESIGN

Resequencing and family-based association testing were used to examine the effect of sequence variation within 100 kb of D19S884 on the reproductive and metabolic phenotypes of PCOS.

SETTING

The study was conducted in an academic medical center.

SUBJECTS

Genetic analyses were performed on DNA obtained from1723 individuals in 412 families with 412 index cases and 43 affected sisters of predominantly European origin (>94%). Genotype-phenotype associations were assessed in 601 women with PCOS and 168 brothers of affected women.

RESULTS

D19S884 allele 8 (A8) within intron 55 of the fibrillin-3 (FBN3) gene showed the strongest evidence for association with PCOS of 53 variants tested (P(corrected) = 0.0037). A8 was also associated with higher levels of fasting insulin and homeostasis model assessment for insulin resistance in women with PCOS and higher fasting levels of proinsulin and proinsulin/insulin ratio in brothers.

CONCLUSIONS

These findings strongly suggest that A8 of D19S884 is the chromosome 19p13.2 PCOS susceptibility locus. The association of D19S884 with markers of insulin resistance and pancreatic beta-cell dysfunction suggests that the same variant contributes to the reproductive and metabolic abnormalities of PCOS in affected women and their brothers.

Polycystic ovary syndrome

Polycystic ovary syndrome is a heterogeneous endocrine disorder that affects about one in 15 women worldwide. The major endocrine disruption is excessive androgen secretion or activity, and a large proportion of women also have abnormal insulin activity. Many body systems are affected in polycystic ovary syndrome, resulting in several health complications, including menstrual dysfunction, infertility, hirsutism, acne, obesity, and metabolic syndrome. Women with this disorder have an established increased risk of developing type 2 diabetes and a still debated increased risk of cardiovascular disease. The diagnostic traits of polycystic ovary syndrome are hyperandrogenism, chronic anovulation, and polycystic ovaries, after exclusion of other conditions that cause these same features. A conclusive definition of the disorder and the importance of the three diagnostic criteria relative to each other remain controversial. The cause of polycystic ovary syndrome is unknown, but studies suggest a strong genetic component that is affected by gestational environment, lifestyle factors, or both.

Polycystic ovary syndrome and its developmental origins

The prenatal testosterone (T)-treated adult female rhesus monkey is one animal model of polycystic ovary syndrome (PCOS) in women, with early prenatal T excess programming a permanent PCOS-like phenotype characterized by luteinizing hormone (LH) hypersecretion from reduced hypothalamic sensitivity to steroid negative feedback and relative insulin excess from increased abdominal adiposity. These combined reproductive and metabolic abnormalities are associated with ovarian hyperandrogenism and follicular arrest in adulthood, as well as premature follicle differentiation and impaired embryo development during gonadotropin therapy for in vitro fertilization (IVF). A second animal model for PCOS, the prenatal T-treated sheep also is characterized by LH hypersecretion from reduced hypothalamic sensitivity to steroid negative feedback, persistent follicles and insulin resistance, but also is associated with intrauterine growth retardation and compensatory growth after birth. The ability of prenatal T excess in both species to alter the developmental trajectory of multiple organ systems in utero provides evidence that the hormonal environment of intrauterine life programs target tissue differentiation, raising the possibility that T excess in human fetal development promotes PCOS in adulthood. Such a hypothesis must include data from clinical studies of PCOS women to clarify the homology between these PCOS-like animal models and PCOS per se in reproductive and metabolic function. Future studies should develop new clinical strategies that improve pregnancy outcome and minimize pregnancy loss in women with disorders of insulin action, including PCOS, obesity and diabetes mellitus as well as minimize transgenerational susceptibility to adult PCOS and its metabolic derangements in male close relatives.

Genetics of polycystic ovarian syndrome

Polycystic ovarian syndrome is a complex disorder with multiple factors affecting its etiology. Elucidation of specific genes and mode of inheritance remains a significant challenge. Linkage and association studies have resulted in over 50 candidate genes as a source of heritable predisposition; however, small sample sizes and failure to reproduce results have hindered efforts. In addition, low fecundity, lack of a male phenotype, and variation of diagnostic criteria represent unique challenges to discovery of polycystic ovarian syndrome genes. A concerted effort will be necessary to conclusively rule in or rule out candidate genes.

Calpain-10 variants and haplotypes are associated with polycystic ovary syndrome in Caucasians

PCOS is known to be associated with an increased risk of T2DM and has been proposed to share a common genetic background with T2DM. Recent studies suggest that the Calpain-10 gene (CAPN10) is an interesting candidate gene for PCOS susceptibility. However, contradictory results were reported concerning the contribution of certain CAPN10 variants, especially of UCSNP-44, to genetic predisposition to T2DM, hirsutism, and PCOS. By means of MALDI-TOF MS technique, we genotyped an expanded single nucleotide polymorphism panel, including the CAPN10 UCSNP-44, -43, -56, ins/del-19, -110, -58, -63, and -22 in a sample of 146 German PCOS women and 606 population-based controls. Statistical analysis revealed an association between UCSNP-56 and susceptibility to PCOS with an odds ratio (OR) of 2.91 (95% CI=1.51-5.61) for women carrying an AA genotype compared with GG. As expected, the 22-genotype of the ins/del-19 variant, which is in high linkage disequilibrium (r2=0.98) with UCSNP-56, was also significantly associated (OR=2.98, 95% CI=1.55-5.73). None of the additionally tested variants alone showed any significant association with PCOS. A meta-analysis including our study (altogether 623 PCOS cases and 1,224 controls) also showed significant association only with ins/del-19. The most common haplotype TGG3AGCA was significantly associated with a lower risk for PCOS (OR=0.487, P=0.0057). In contrast, the TGA2AGCA haplotype was associated with an increased risk for PCOS (OR=3.557, P=0.0011). By investigating a broad panel of CAPN10 variants, our results pointed to an allele dose-dependent association of UCSNP-56 and ins/del-19 with PCOS.