Association between polymorphisms of the CYP11A1 gene and polycystic ovary syndrome in Chinese women

Integrated transcriptomic analysis on chicken ovary reveals CYP21A1 affects follicle granulosa cell development and steroid hormone synthesis

Egg production is an economically important trait in poultry breeding and production. Follicular development was regulated by several hormones released and genes expressed in the granulosa cells, impacting the egg production and fecundity of hens. However, the molecular functions of these candidate genes that modulate these processes remain largely unknown. In the present study, bioinformatics analyses were performed to identify the candidate genes related to egg production in the ovarian tissue of White Leghorns with high egg production and Beijing You chicken with low egg production during sexual maturity and peak laying periods. The ovarian granulosa cells were used to assess the function of CYP21A1 by transfecting with CYP21A1-specific small interfering RNAs (siRNAs) and overexpression plasmids. We identified 514 differentially expressed genes (|Log2(fold change) | >1, P <0.05) between the 2 chicken breeds in both laying periods. Among these genes, CYP21A1, which is involved in the steroid hormone biosynthesis pathway was consistently upregulated in White Leghorns. Weighted gene co-expression network analysis (WGCNA) further suggested that CYP21A1 was a hub gene, which could positively respond to treatment with follicle stimulation hormone (FSH), affecting egg production. The interference of CYP21A1 significantly inhibited cell proliferation and promoted cell apoptosis. Overexpression of CYP21A1 promotes cell proliferation and inhibits cell apoptosis. Furthermore, the interference with CYP21A1 significantly downregulated the expression of STAR, CYP11A1, HSD3B1, and FSHR and also decreased the synthesis of progesterone (P4) and estradiol (E2) in granulosa cells. Overexpression of CYP21A1 increased the synthesis of P4 and estradiol E2 and the expression of steroid hormone synthesis-related genes in granulosa cells. Our findings provide new evidence for the biological role of CYP21A1 on granulosa cell proliferation, apoptosis, and steroid hormone synthesis, which lays the theoretical basis for improving egg production.

Association of CYP11A1 Polymorphisms with Recurrent Pregnancy Loss in the Female Population of Punjab

Background

Recurrent pregnancy loss (RPL) is defined as the failure of two or more clinically recognised pregnancies before 20 weeks of gestation. The prevalence of clinically evident RPL is 1%-2% worldwide. The aetiologies of RPL include uterine anatomic anomalies, uncontrolled diabetes mellitus, untreated hypothyroidism, parental chromosomal abnormalities, antiphospholipid antibody syndrome, thrombophilia, genetic abnormalities and infections.

Aims

This study was aimed at investigating the possible association between CYP11A1 (rs11632698) and (rs4077582) polymorphisms with RPL in the female population of Punjab.

Settings and Design

The case- control study was conducted on 170 subjects, of which 80 RPL cases and 90 controls were analysed.

Materials and Methods

Genotypic analysis was performed using the polymerase chain reaction - restriction fragment length polymorphism.

Statistical Analysis Used

Pearson's Chi-square test was used.

Results

The genotypic frequency of CYP11A1 (rs11632698) A > G polymorphism was statistically significantly different amongst cases and controls (P = 0.00001). It was observed that the presence of the G allele might increase the risk of RPL. A Chisquare analysis of CYP11A1 (rs4077582) (P = 0.01) indicated a significant difference amongst the genotypes of cases and controls of RPL.

Conclusion

CYP11A1 variants (rs11632698 and rs4077582) may be useful markers in determining the genetic susceptibility to the pathogenesis of RPL. Keywords: CYP11A1, recurrent miscarriage, recurrent pregnancy loss, rs11632698, rs4077582, spontaneous abortion.

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.

In-Silico Investigation of Effects of Single-Nucleotide Polymorphisms in PCOS-Associated CYP11A1 Gene on Mutated Proteins

Polycystic ovary syndrome (PCOS) is a reproductive disorder with multiple etiologies, mainly characterized by the excess production of androgens. It is equally contributed to by genes and environment. The CYP11A1 gene is imperative for steroidogenesis, so any dysregulation or mutation in this gene can lead to PCOS pathogenesis. Therefore, nucleotide diversity in this gene can be helpful in spotting the likelihood of developing PCOS. The present study was initiated to investigate the effect of single nucleotide polymorphisms in human CYP11A1 gene on different attributes of encoded mutated proteins, i.e., sub-cellular localization, ontology, half-life, isoelectric point, instability index, aliphatic index, extinction coefficient, 3-D and 2-D structures, and transmembrane topology. For this purpose, initially coding sequence (CDS) and single nucleotide polymorphisms (SNPs) were retrieved for the desired gene from Ensembl followed by translation of CDS using EXPASY tool. The protein sequence obtained was subjected to different tools including CELLO2GO, ProtParam, PHYRE2, I-Mutant, SIFT, and PolyPhen. It was found that out of seventy-eight SNPs analyzed in this project, seventeen mutations, i.e., rs750026801 in exon 1, rs776056840, rs779154292 and rs1217014229 in exon 2, rs549043326 in exon 3, rs755186597 in exon 4, rs1224774813, rs757299093 and rs1555425667 in exon 5, rs1454328072 in exon 7, rs762412759 and rs755975808 in exon 8, and rs754610565, rs779413653, rs765916701, rs1368450780, and rs747901197 in exon 9 considerably altered the structure, sub-cellular localization, and physicochemical characteristics of mutated proteins. Among the fifty-nine missense SNPs documented in present study, fifty-five and fifty-three were found to be deleterious according to SIFT and PolyPhen tools, respectively. Forty-nine missense mutations were analyzed to have a decreasing effect on the stability of mutant proteins. Hence, these genetic variants can serve as potential biomarkers in human females for determining the probability of being predisposed to PCOS.

Transcriptome Analysis and Identification of the Cholesterol Side Chain Cleavage Enzyme BbgCYP11A1 From Bufo bufo gargarizans

Bufo bufo gargarizans Cantor are precious medicinal animals in traditional Chinese medicine (TCM). Bufadienolides as the major pharmacological components are generated from the venomous glands of B. bufo gargarizans. Bufadienolides are one type of cardiac aglycone with a six-member lactone ring and have properties of antitumor, cardiotonic, tonsillitis, and anti-inflammatory. The biosynthesis of bufadienolides is complex and unclear. This study explored the transcriptome of three different tissues (skin glands, venom glands, and muscles) of B. bufo gargarizans by high-throughput sequencing. According to the gene tissue–specific expression profile, 389 candidate genes were predicted possibly participating in the bufadienolides biosynthesis pathway. Then, BbgCYP11A1 was identified as a cholesterol side chain cleaving the enzyme in engineering yeast producing cholesterol. Furthermore, the catalytic activity of BbgCYP11A1 was studied with various redox partners. Interestingly, a plant NADPH-cytochrome P450 reductase (CPR) from Anemarrhena asphodeloides showed notably higher production than BbgAdx-2A-BbgAdR from B. bufo gargarizans. These results will provide certainly molecular research to reveal the bufadienolides biosynthesis pathway in B. bufo gargarizans.

A Review on CYP11A1, CYP17A1, and CYP19A1 Polymorphism Studies: Candidate Susceptibility Genes for Polycystic Ovary Syndrome (PCOS) and Infertility

Polycystic ovary syndrome is a multifactorial condition associated with reproductive and endocrine organs and might cause infertility and metabolic abnormalities in childbearing age. PCOS seems to be a multifactorial disorder resulting from the combination of several genetic and environmental factors. Little research has been conducted to date on the impact of polymorphisms in infertility. We aim to review the appearance of polymorphisms in females of diverse ethnicities and their effect on infertility in the population with polycystic ovary syndrome. There have been numerous reports of the importance of the steroidogenesis pathway and genetic variants in PCOS pathogenesis. The most important genes that play a role in the aetiology of PCOS are CYP11A1, CYP17A1, and CYP19A1. We evaluated the occurrence of polymorphisms in various ethnicities in the CYP11A1, CYP17A1, and CYP19A1 genes and their efficacy on increasing PCOS risk with infertility. Our findings revealed that polymorphisms in various ethnicities are associated with the risk of PCOS with infertility. Although conflicting results regarding CYP11A1, CYP17A1, and CYP19A1 polymorphisms and their influence on PCOS with infertility have been reported in a small number of papers, the authors feel this may be attributable to the sample size and ethnic composition of the examined populations. In conclusion, our study strongly suggests that the CYP11A1, CYP17A1, and CYP19A1 genes might significantly enhance the probability of developing PCOS with infertility.

An update on polycystic ovary syndrome: A review of the current state of knowledge in diagnosis, genetic etiology, and emerging treatment options

Polycystic ovary syndrome is the most common endocrine disorder in women of reproductive age, which is still incurable. However, the symptoms can be successfully managed with proper medication and lifestyle interventions. Despite its prevalence, little is known about its etiology. In this review article, the up-to-date diagnostic features and parameters recommended on the grounds of evidence-based data and different guidelines are explored. The ambiguity and insufficiency of data when diagnosing adolescent women have been put under special focus. We look at some of the most recent research done to establish relationships between different gene polymorphisms with polycystic ovary syndrome in various populations along with the underestimated impact of environmental factors like endocrine-disrupting chemicals on the reproductive health of these women. Furthermore, the article concludes with existing treatments options and the scopes for advancement in the near future. Various therapies have been considered as potential treatment through multiple randomized controlled studies, and clinical trials conducted over the years are described in this article. Standard therapies ranging from metformin to newly found alternatives based on vitamin D and gut microbiota could shine some light and guidance toward a permanent cure for this female reproductive health issue in the future.

Association Analysis of CYP11A1 Variants with Polycystic Ovary Syndrome: a Case-Control Study from North India

The most common multifactorial endocrine disorder in females of reproductive age is polycystic ovary syndrome (PCOS), affecting about 5-10% of females worldwide and 9.3% of females in India. Androgen excess in PCOS is caused as a result of defects in steroidogenesis genes. CYP11A1 is an imperative marker in the steroid synthesis pathway, and the altered expression of CYP11A1 has been reported to disrupt the synthesis of steroids and hence conferring risk for the development of PCOS. The present study aimed to analyze genetic variants (rs11632698, rs4077582, rs4887139) of CYP11A1 with PCOS from North India. The study included 270 PCOS females diagnosed according to Rotterdam 2003 criteria and 270 age-matched healthy non-PCOS females. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used for the genotypic analysis of the selected genetic variants. Association analysis of biochemical parameters (cholesterol, triglyceride, high-density lipoprotein) and anthropometric measurements with PCOS cases was done. The genetic variants of CYP11A1 (rs11632698, rs4077582, and rs4887139) demonstrated significant association with PCOS cases (p=1.0E-12, p=3.0E-3, p=1.0E-2, respectively). Binary logistic regression revealed that the dominant model of rs11632698 conferred 2.0 risk, and dominant as well as the co-dominant model of rs4887139 conferred risk of 2.2 and 2.4 fold, respectively, towards the progression of PCOS. The overall mean triglyceride levels were elevated, and mean HDL levels were lower in PCOS cases as compared to threshold values. The significant association of studied genetic variants suggested the important role of CYP11A1 in susceptibility to PCOS. The study was the first of its kind from our region and provided baseline data of genetics of PCOS.

Polymorphism, expression and structure analysis of key genes in the ovarian steroidogenesis pathway in sheep (Ovis aries)

Background

Litter size is an important factor that significantly affects the development of the sheep industry. Our previous TMT proteomics analysis found that three key proteins in the ovarian steroidogenesis pathway, STAR, HSD3B1, and CYP11A1, may affect the litter size trait of Small Tail Han sheep.

Objective

The purpose of this study was to better understand the relationship between polymorphisms of these three genes and litter size.

Material and Method

Sequenom MassARRAY detected genetic variance of the three genes in 768 sheep. Real‐time qPCR of the three genes was used to compare their expression in monotocous and polytocous sheep in relevant tissues. Finally, bioinformatics analysis predicted the protein sequences of the different SNP variants.

Result

Association analysis showed that there was a significant difference in litter size among the genotypes at two loci of the CYP11A1 gene (p < 0.05), but no significant difference was observed in litter size among all genotypes at all loci of the STAR and HSD3B1 genes (p > 0.05). However, STAR expression was significantly different in polytocous and monotocous sheep in the pituitary (p < 0.01). Tissue‐specific expression in the ovary was observed for HSD3B1 (p < 0.05), but its expression was not different between polytocous and monotocous sheep. Bioinformatics analysis showed that the g.33217408C > T mutation of CYP11A1 resulted in major changes to the secondary and tertiary structures. In contrast, gene polymorphisms in STAR and HSD3B1 had minimal impacts on their protein structures.

Discussion

This may explain why the CYP11A1 variant impacted litter size while the others did not. The single nucleotide polymorphism of the CYP11A1 gene would serve as a good molecular marker when breeding to increase litter size in sheep. Our study provides a basis for further revealing the function of the ovarian steroidogenesis pathway in sheep reproduction and sheep breeding.

Genetic estrogen receptor alpha gene PvuII polymorphism in susceptibility to knee osteoarthritis in a Chinese Han population: A southern Jiangsu study

BACKGROUND

Knee osteoarthritis (KOA) is the most prevalent type of arthritis and genetic factors play an important role in KOA pathogenesis. Some studies have reported the association of estrogen receptor alpha (ESRα) gene polymorphism and KOA susceptibility in different populations. This study was designed to verify whether ESRα gene polymorphism (rs2234693) was associated with primary KOA in a Chinese Han population living in the south of Jiangsu.

METHODS

A case-control association study on single nucleotide polymorphism (SNP) rs2234693 was performed, and a total of 1953 subjects (1033 OA cases and 920 controls) were genotyped. Allele and genotype frequencies were compared between KOA cases and control participants.

RESULTS

SNP rs2234693 was significantly associated with KOA in the dominant genetic model (TT + TC vs. CC) in all the subjects (odds ratio (OR) = 1.30; 95% confidence interval (CI) = 1.02-1.66; P = .03), and T allele frequency was also higher compared with allele C (OR = 1.38; 95% CI = 1.06-1.80; P = .02). After stratification by gender, there was no evident difference between the two groups in female and male subjects (P > .05). With a stratification for KOA severity, the combined genotype (TT + TC) (OR = 1.47; 95% CI = 1.12-1.94; P < .01) and T allele (OR = 1.61; 95% CI = 1.19-2.19; P < .01) were evidently associated with mild KOA, but not with severe KOA.

CONCLUSIONS

ESRα gene is of considerable importance in the pathogenesis of early-stage KOA in a Chinese Han population living in southern Jiangsu.

Putative functional variants of PI3K/AKT/mTOR pathway are associated with knee osteoarthritis susceptibility

BACKGROUND

Osteoarthritis (OA) is a degenerative musculoskeletal disease which causes joint deformity and pain and finally leads to limb dysfunction. Knee osteoarthritis (KOA) has the highest incidence among all kinds of OA. Strong evidence leads to the understanding that P13K/AKT/mTOR signaling is very important in cartilage degeneration.

METHODS

This research sought to understand the association between genetic variation of PI3K/AKT/mTOR genes and KOA susceptibility among Chinese population. All the genetic variants of PI3K/AKT/mTOR pathway were graded and selected using RegulomeDB database, and then, an association study including 278 osteoarthritis patients and 289 controls was conducted.

RESULTS

Finally, eight SNPs' genotypes' distributions and susceptibility to KOA were presented. AKT1 rs2498789 was associated with KOA susceptibility in dominate genetic model (AA + GA vs GG) after adjusted for BMI, age, and gender: OR = 1.46, 95% CI: 1.03-2.05, P = .03. PIK3CA rs7646409 was also associated with KOA susceptibility (TC vs TT) after adjusted for BMI, age, and gender: OR = 0.58, 95% CI: 0.36-0.93, P = .02. PIK3CA rs7646409 (TC vs TT) with KOA risk was more significant in age < 60 group (P for heterogeneity was .03). Risk score showed significant association with KOA susceptibility after cumulative analysis (OR = 2.45, 95% CI: 1.35-4.45, P = .003).

CONCLUSIONS

This study shows that genetic variation of PI3K/AKT/mTOR is associated with KOA susceptibility in Chinese Han population, indicating that PI3K/AKT/mTOR is very important in KOA pathogenesis.

Identifying genes associated with the development of human polycystic ovary syndrome

The pathophysiology of polycystic ovary syndrome (PCOS) is confusing until today as it is a multifactorial endocrine disorder. It is presented with altered gonadotropin levels, bulky multi-follicular ovaries, infertility, and obesity. This complex pathophysiology is linked with insulin resistance and hyperandrogenism. Hyperandrogenemia significantly contributes towards cosmetic anomalies including hirsutism, acne, and alopecia in the PCOS women. The preexisting insulin resistance in women with PCOS is likely to aggravate the increased levels of androgen. The review findings have shown that in the steroidogenic pathway, ovarian steroidogenesis patterns classify mainly towards the hypertrophy of theca cells along with alteration in the expression of key enzymes. The association of polymorphisms in genes encoding the process of an intricate cascade of steroidogenesis is delineated. The emergence of an unanimously accepted genetic marker for susceptible PCOS was affected based on inconsistent findings. The present study has provided a comprehensive summary of the impact of polymorphisms among the common androgen-related genes to govern the genetic predisposition.

Hyperandrogenism in polycystic ovarian syndrome and role of CYP gene variants: a review

Background

Polycystic ovary syndrome (PCOS) is a multifactorial endocrine disorder characterized by anovulation, hyperandrogenism, and polycystic ovarian morphology. The pathophysiology of PCOS is not clear; however, disturbance in hypothalamic-pituitary-ovarian axis and abnormal steroidogenesis along with genetic and environmental factors act as main contributors to this disorder.

Main text

Hyperandrogenism, the hallmark feature of PCOS, is clinically manifested as hirsutism, acne, and alopecia. Excessive androgen production by ovaries as well as from adrenals contributes to hyperandrogenism. Abnormalities in the neuroendocrine system like increased pulse frequency of gonadotropin-releasing hormone, stimulating the pituitary for excessive production of luteinizing hormone than that of follicle-stimulating hormone is seen in PCOS women. Excess LH stimulates ovarian androgen production, whereas a relative deficit in FSH impairs follicular development. The imbalance in LH: FSH causes proliferation of ovarian theca cells leading to increased steroidogenesis, and ultimately leading to hyperandrogenism in PCOS women. Various genetic factors have been shown to be associated with abnormal steroidogenesis. CYP genes involved in steroidogenesis play an important role in androgen production and are considered as key players in hyperandrogenism in PCOS.

Conclusion

Polymorphisms in CYP genes can aggravate the hyperandrogenic phenotype in women with PCOS by either upregulating or downregulating their expression, thus increasing androgens further. However, this hypothesis needs to be validated by further studies.

Polycystic ovary syndrome (PCOS) and genetic predisposition: A review article

Polycystic ovary syndrome (PCOS) is a heterogeneous condition which is related to an endocrine reproductive disorder of females. It affects females of 18-44 age. The persistent hormonal disbalance leads to the complexities such as numerous cysts, an irregular menstrual cycle that ultimately leads to infertility among females. Many candidate genes have been identified to be one of the causes of PCOS. Different studies have been carried out to find the genetic correlation of PCOS. It is essential to carry out such studies that identify the clear cause of PCOS and its genetic association and hormonal disbalance. This review has highlighted different genes and their correlation with PCOS that leads to hormonal disbalance. Yet not in-depth but an attempt to study the genetic predisposition of PCOS.

Expression of genes controlling steroid metabolism and action in granulosa-lutein cells of women with polycystic ovaries

INTRODUCTION

Aberrant function of granulosa cells has been implicated in the pathophysiology of PCOS.

MATERIALS & METHODS

Granulosa lutein (GL) cells were collected during oocyte retrieval for IVF/ICSI. RT-qPCR was used to compare gene expression between 12 control women, 12 with ovulatory PCO and 12 with anovulatory PCOS. To examine which genes are directly regulated by androgens, GL cells from an additional 12 control women were treated in-vitro with 10 nM dihydrotestosterone (DHT).

RESULTS

GL cells from women with PCOS showed reduced expression of CYP11A1 3-fold (p = 0.005), HSD17B1 1.8-fold (p = 0.02) and increased expression of SULT1E1 7-fold (p = 0.0003). Similar results were seen in ovulatory women with PCO. GL cells treated with 10 nM DHT showed a 4-fold (p = 0.03) increase in expression of SULT1E1 and a 5-fold reduction in SRD5A1 (p = 0.03).

CONCLUSIONS

These findings support the notion that aberrant regulation of steroid metabolism or action play a part in ovarian dysfunction in PCOS.

Putative functional variants of lncRNA identified by RegulomeDB were associated with knee osteoarthritis susceptibility

BACKGROUND

Knee osteoarthritis (KOA) is the most common form of chronic degenerative joint disease worldwide. Its incidence has increased in recent years. Aberrant expression profile of lncRNAs in damaged bone and cartilage of KOA patients has been reported recently, indicating its potential contributions in KOA development and a promising target for disease diagnosis and treatment. The aim of this study was to identify the association between genetic variation in lncRNA and KOA.

METHODS

We retrieved relevant articles from the PubMed, Medline and Embase databases up to Jul 2017 investigating the association between lncRNA and the risk of osteoarthritis. There are 15 lncRNAs which show connection with osteoarthritis. We selected potential functional polymorphisms identified by RegulomeDB database in these lncRNAs. A case-control study was conducted which contained 278 KOA patients and 289 OA-free controls.

RESULTS

Logistic regression analyses revealed that H19 rs2067051 T allele was significantly associated with decreased risk of KOA after adjusted for age, gender and BMI in recessive genetic model (OR = 0.63, P = 0.03) and additive genetic model (OR = 0.79, P = 0.03). MEG3 rs4378559 T allele was significantly associated with increased risk of KOA in additive genetic model (OR = 1.32, P = 0.04). Heterogeneity tests proved that H19 rs2067051, MEG3 rs4378559 and HOTTIP rs202384's risk effects on KOA were more remarkable for female, BMI ≥ 25 and younger age (age < 60), respectively.

CONCLUSION

The results indicate that potential functional genetic variation in lncRNA plays an important role in the pathogenesis of KOA.

Genetic Variants Associated with Hyperandrogenemia in PCOS Pathophysiology

Polycystic ovary syndrome is a multifactorial endocrine disorder whose pathophysiology baffles many researchers till today. This syndrome is typically characterized by anovulatory cycles and infertility, altered gonadotropin levels, obesity, and bulky multifollicular ovaries on ultrasound. Hyperandrogenism and insulin resistance are hallmark features of its complex pathophysiology. Hyperandrogenemia is a salient feature of PCOS and a major contributor to cosmetic anomalies including hirsutism, acne, and male pattern alopecia in affected women. Increased androgen levels may be intrinsic or aggravated by preexisting insulin resistance in women with PCOS. Studies have reported augmented ovarian steroidogenesis patterns attributed mainly to theca cell hypertrophy and altered expression of key enzymes in the steroidogenic pathway. Candidate gene studies have been performed in order to delineate the association of polymorphisms in genes, which encode enzymes in the intricate cascade of steroidogenesis or modulate the levels and action of circulating androgens, with risk of PCOS development and its related traits. However, inconsistent findings have impacted the emergence of a unanimously accepted genetic marker for PCOS susceptibility. In the current review, we have summarized the influence of polymorphisms in important androgen related genes in governing genetic predisposition to PCOS and its related metabolic and reproductive traits.

MAPK and ERK polymorphisms are associated with PCOS risk in Chinese women

In this case-control study, we analyzed the association between eight RegulomeDB-annotated single nucleotide polymorphisms (SNPs) in the MEK1, MEK2, ERK1 and ERK2 genes and polycystic ovarian syndrome (PCOS). Logistic regression analysis demonstrated that MEK1 rs12050732 (OR = 1.29 [95%CI: 1.06-1.58], P = 0.012), ERK2 rs2266966 (OR = 0.81 [95%CI: 0.67-0.99], P = 0.040) and ERK2 rs5999521 (OR = 0.66 [95%CI: 0.51-0.86], P = 0.002) were associated with PCOS risk without adjusting for age and body mass index. Moreover, PCOS risk increased with allele dosage when these three polymorphisms were combined (P_trend = 0.001). These findings suggest that genetic variants in key MAPK and ERK genes contribute to PCOS risk in Chinese women.

Association analysis between the polymorphisms of HSD17B5 and HSD17B6 and risk of polycystic ovary syndrome in Chinese population

OBJECTIVE

To assess whether single nucleotide polymorphisms of HSD17B5 (AKR1C3) (rs1937845 and rs12529) and HSD17B6 (rs898611) are associated with polycystic ovary syndrome (PCOS) in a Chinese population.

DESIGN

A case-control study was conducted to investigate the relation between HSD17B5 and HSD17B6 polymorphisms and PCOS.

METHODS

In this study, 335 patients with PCOS and 354 controls were recruited. The genotypes of HSD17B5 (rs1937845 and rs12529) and HSD17B6 (rs898611) were detected by the TaqMan method.

RESULTS AND CONCLUSIONS

We found that the genotypic frequencies of the rs1937845 polymorphism were different in subjects with PCOS compared with control, with the CT genotype being more commonly found in patients with PCOS than in controls (P=0.005). We observed a significantly 1.74-fold higher risk of CT genotype in the polymorphism rs1937845 in women with PCOS vs the control group (adjusted odds ratio (OR), 1.74; 95% CI=1.19-2.54; P=0.005). A similar, significant 1.47-fold higher risk (adjusted OR, 1.47; 95% CI=1.07-2.03; P=0.018) was demonstrated for T allele of polymorphism rs1937845 associated with PCOS. In patients with PCOS, the rs12529 (G>C) and rs1937845 (C>T) polymorphisms were strongly associated with the high level of testosterone. The TT carriers of polymorphism rs1937845 had a significantly increased homeostatic model assessment-B% (HOMA-B%) (P=0.045) and that might be associated with the high risk of insulin resistance. However, no significant difference was found in genotype or allele distributions of the polymorphisms rs12529 of HSD17B5 and rs898611 of HSD17B6 between patients with PCOS and controls. Additionally, the two polymorphisms of HSD17B5 are associated with hyperandrogenemia in patients with PCOS. In conclusion, our findings showed a significant statistical association between HSD17B5 rs1937845 and PCOS risk in Chinese women. The CT genotype and T allele frequency are influenced significantly to a higher extent in patients with PCOS than controls. Further studies are needed to confirm the results and find out the exact molecular mechanism of the polymorphism on the risk of hyperandrogenemia and PCOS.

CYP11A1 microsatellite (tttta)n polymorphism in PCOS women from South India

BACKGROUND

Polycystic ovary syndrome (PCOS) is a condition with central feature of hyperandrogensism that affects 5-12 % of women worldwide. P450sec the cholesterol side chain cleavage enzyme encoded by CYP11A1 gene is instrumental in the synthesis of sex hormones. A promoter pentanucleotide repeat (tttta)(n) polymorphism of this gene is reported to be associated with several hormone related diseases including PCOS. Here we aimed to examine the involvement of CYP11A1 polymorphism with PCOS susceptibility in a case-control study conducted among South Indian women.

METHODS

A total of 542 subjects comprised of 267 PCOS patients and 275 controls were recruited. DNA was extracted from blood and CYP11A1 (tttta)(n) polymorphism was genotyped by PCR-PAGE.

RESULTS

Fifteen different alleles ranging between 2-16 repeats were identified in the studied group and the most frequent allele observed in controls was of 8 repeats. The presence of >8 repeat allele was common in patients (64 % vs. 38 %) and showed a three-fold risk for PCOS susceptibility than controls (OR = 2.93; p < 0.05). PCOS women with higher BMI were markedly elevated in early quartile (p < 0.05).

CONCLUSION

CYP11A1 (tttta)(n) repeat polymorphism appeared to be a potential molecular marker for PCOS risk in our population. Gene-gene and gene-environmental interactions with respect to obesity may play a role in the early onset of this multifactorial condition. This is the first report from South India; however, replicative studies considering other probable causative factors for PCOS risk are warranted.

Polymorphisms of pentanucleotide repeats (tttta)n in the promoter of CYP11A1 and their relationships to polycystic ovary syndrome (PCOS) risk: a meta-analysis

Polycystic ovary syndrome (PCOS) is one of the most common endocrine diseases with an uncertain pathology and the most frequent incretory disorder in women of reproductive age, often leading to female infertility. Evidence has shown that genetic factors may contribute to the etiology of PCOS. Contradictory results have been reported concerning the association between PCOS and the CYP11A1 gene promoter -528 bp pentanucleotide (tttta)n repeat polymorphism. In order to get an overall understanding of the association between the CYP11A1 gene promoter -528 bp pentanucleotide (tttta)n repeat polymorphism and PCOS, case-control studies regarding this association were extracted from MEDLINE, Ovid EMBASE and PubMed and pooled for meta-analysis. In dichotomous allelic analyses with 1,236 PCOS patients and 1,306 control subjects, the odds ratios (ORs) were very close to 1. In dichotomous genotypic analyses with 1,063 PCOS patients and 1,176 control subjects, the (tttta)4 genotype may increase the risk of PCOS in a recessive model with OR 1.44, 95% confidence interval (CI) 1.12-1.85, and the (tttta)6 genotype may decrease the risk of PCOS in a dominant model with OR 0.76, 95% CI 0.61-0.93. In continuous analyses with 1,085 PCOS patients and 1,216 control subjects, the Mean Difference (MD) was -0.07 with a 95% CI -0.18 to 0.05, showing no difference between PCOS and control groups. No publication bias was found in either dichotomous or continuous analyses. Taken together, there may be an association between CYP11A1 promoter pentanucleotide repeat polymorphism and PCOS. Further research is needed to strictly confirm our findings.

Association between vaspin rs2236242 gene polymorphism and polycystic ovary syndrome risk

Vaspin, an adipocytokine that has been isolated from the visceral adipose tissue, is a member of the serine protease inhibitor family. In humans, serum vaspin levels are correlated with body mass index (BMI) and obese women with polycystic ovary syndrome (PCOS). The present study is the first investigation to examine the association between vaspin rs2236242 gene polymorphism and risk of PCOS in Iranian patients. This case-control study was performed on 150 patients with PCOS and 150 healthy women. The vaspin genotypes were determined using tetra-amplification refractory mutation system-polymerase chain reaction (T-ARMS-PCR). Our finding showed that there are significant differences in genotype frequencies between case and control group regarding vaspin rs2236242 polymorphism (OR=0.59, CI=0.37-0.95, p=0.03). The A allele decreased the risk of PCOS (OR=0.67, CI=0.46-0.96, p=0.03) as compared to the T allele. There was no significant association between vaspin rs2236242 gene polymorphism and PCOS after adjusting genotypes for BMI. In conclusion, our data suggest a significant association between vaspin rs2236242 polymorphism and the PCOS but this relationship is affected by obesity status.

Association between FSHR polymorphisms and polycystic ovary syndrome among Chinese women in north China

Purpose

Polycystic ovary syndrome (PCOS) is a common endocrine disorder disease among women in reproductive-age. Since follicle stimulating hormone (FSH) exerts important biological functions, the association between PCOS and FSH receptor (FSHR) polymorphisms attracts wide attention. The aim of this study was to evaluate whether polymorphisms of FSHR at 307 and 680 codons are associated with PCOS patients in China.

Methods

Patients with PCOS (n = 215) and controls (n = 205) were recruited from Shanxi Province in north China. They are Han ethnics. Genomic DNA was isolated from the venous blood. The Ala307Thr and Ser680Asn polymorphisms of FSHR were analyzed by polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) and direct DNA sequencing.

Results

The distributions of genotype and allele of Ala307Thr and Ser680Asn polymorphisms of FSHR were not statistically different between the PCOS patients and the controls. Analysis of the frequency of FSHR polymorphisms showed no statistical difference among the PCOS patients with different obesity standards. Although there were no statistical differences in the most of the endocrine parameters including LH, LH/FSH, E2, P and T as well as the clinical pregnancy rate, there were significant differences in the levels of FSH and PRL among PCOS patients carrying different genotypes of Ala307Thr and Ser680Asn polymorphisms.

Conclusion

The Ala307Thr and Ser680Asn polymorphisms of FSHR are not associated with PCOS in Han ethnic Chinese women in north China. The FSHR polymorphisms was related to the levels of FSH and PRL but not other PCOS-associated endocrine hormones as well as clinical pregnancy rate in PCOS patients of Han Chinese ethnical population.

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

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