Susceptibility loci identified in Han Chinese influence genetic predisposition of PCOS in Indian women.

BACKGROUND: Polycystic ovary syndrome (PCOS) is a multifactorial disorder characterized by a broad spectrum of reproductive and metabolic perturbations, necessitating early timely diagnosis and management. PCOS is a multigenic disorder and ample evidence from family based, candidate gene and genome-wide association studies (GWAS) has implicated genetic factors in development and progression of PCOS. The first GWASs in Han Chinese population revealed prominent gene loci to be strong contenders in the etiopathogenesis of PCOS. However, different ethnic and geographical settings impact the genetic association pattern of PCOS. METHODS AND RESULTS: In the current case-control replication study, we have genotyped previously identified polymorphisms viz. rs2479106 and rs10818854 of DENND1A and rs13405728 of LHCGR, rs4385527 and rs3802457 of c9orf3, rs705702 of RAB5B and rs1894116 of YAP1 in control (N = 247) and PCOS (N = 504) women by Sanger sequencing, and their association with PCOS susceptibility and its related traits was investigated. We found significant association of rs4385527 of c9orf3 and rs1894116 of YAP1 with decreased and increased PCOS susceptibility respectively in non-hyperandrogenic women. Trend towards association was also noted for rs2479106 of DENND1A and rs705702 of RAB5B. Additionally, polymorphisms also showed association with metabolic and androgen related traits in both controls and hyper- and non-hyperandrogenic women with PCOS. CONCLUSIONS: Thus, this study shows that some, but not all polymorphisms previously identified in Han Chinese women, could contribute to the genetic pathophysiology of PCOS in Indian women, accentuating essentiality of conducting replication studies to elucidate the genetic predisposition profile of PCOS.

Investigating the association of previously identified genome-wide significant loci (rs10739076 and rs1784692) with PCOS susceptibility and its related traits in Indian women.

OBJECTIVE(S): Polycystic ovary syndrome (PCOS) is a multifactorial endocrinopathy with an enigmatic etiology. Hallmark features include irregular menstrual cycles, insulin resistance and hyperandrogenemia and affected women are prone to development of adverse reproductive and cardiometabolic outcomes like anovulatory infertility, impaired glucose tolerance, type 2 diabetes, dyslipidemia, metabolic syndrome and cardiovascular disease. Genetic underpinnings of PCOS have been investigated extensively using genome-wide association studies, which have led to the identification of several novel susceptibility loci. However, as ethnic diversity contributes to phenotypic and genetic heterogeneity, we undertook the first genetic association study to determine the association of rs10739076 of PLGRKT and rs1784692 of ZBTB16 with PCOS susceptibility and its related traits in Indian women. STUDY DESIGN: The present case-control study comprised 497 women with PCOS diagnosed according to the Rotterdam criteria and 233 age matched healthy women as controls. All participants were characterized in terms of anthropometric, hormonal and metabolic parameters and the variants were investigated by direct sequencing. Genotypic and genotype-phenotype association of these variants with PCOS susceptibility and its related biochemical and hormonal traits was analyzed with appropriate statistical tests. RESULTS: The genotypic and allelic frequencies of rs1784692 of ZBTB16 were significantly decreased in lean women with PCOS only, and this variant was associated with lowered insulin levels, HOMA-IR, LH:FSH ratio along with increased ApoA1 levels and QUICKI in them. Although, the PLGRKT variant, rs10739076, showed similar frequency distribution in both lean and obese groups, it was found to be associated with reduced fasting glucose in all women with PCOS. CONCLUSION(S): To the best of our knowledge, this is the first study to demonstrate that ZBTB16 variant showed significant association with reduced PCOS susceptibility in lean rather than obese Indian women, highlighting the impact of obesity on determining genetic predisposition to PCOS in Indian women. In contrast, PLGRKT variant did not influence PCOS risk in lean or obese women. Importantly, both variants exerted a protective effect on glucose metabolism, insulin resistance, gonadotropin and lipid levels in women with PCOS. Determination of susceptibility variants for PCOS demand population specific replication studies to ascertain best candidate loci for PCOS.

Altered redox status may contribute to aberrant folliculogenesis and poor reproductive outcomes in women with polycystic ovary syndrome.

BACKGROUND: Women with polycystic ovary syndrome (PCOS) are often infertile and opt for artificial reproductive techniques (ART) to conceive. Disrupted pro-/antioxidant balance in oocyte microenvironment may contribute towards sub-optimal oocyte/embryo quality and poor ART outcome in them. METHODS: Activities/levels of redox markers and their transcript expression were investigated in follicular fluid and granulosa cells respectively, in women with PCOS (n = 71) and controls (n = 50) undergoing in vitro fertilization (IVF). Correlation analysis of redox markers and IVF parameters was performed. RESULTS: Activities of superoxide dismutase, glutathione reductase, glutathione peroxidase, and paraoxonase1 were significantly lower in follicular fluid of PCOS women than in controls. Levels of lipid peroxidation, oxidative protein modification, and oxidized glutathione were higher, whereas those of total antioxidant capacity, total thiols, and reduced glutathione were lower in follicular fluid of PCOS women than in controls. Further, comparison of redox markers based on insulin resistance and BMI status of study participants showed similar trends, indicating that PCOS pathophysiology is a significant contributor to oxidative stress irrespective of insulin resistance and BMI. Transcript levels of antioxidant enzymes were lower in granulosa cells from PCOS women than in controls, and they accorded with their activities in follicular fluid. Moreover, few redox markers showed significant correlations with oocyte/embryo quality and pregnancy outcome. CONCLUSION: Our data indicates disrupted redox homeostasis in follicular environment in PCOS which may negatively influence oocyte/embryo quality. Further, granulosa cells may play crucial role in maintaining follicular redox homeostasis. Glutathione system and paraoxonase1 could be explored further as surrogates for IVF prognosis/outcome.

Replication study of THADA rs13429458 variant with PCOS susceptibility and its related traits in Indian women.

AIM: The aetiopathogenesis of the multigenic multifactorial endocrinopathy, polycystic ovary syndrome (PCOS) has been explored using linkage, candidate gene and genome-wide association studies. Contradictory reports of replication studies attributed to phenotypic, ethnic and geographic variations are available. In this study, we investigated the association of Han Chinese GWAS polymorphism (rs13429458) in thyroid adenoma-associated gene (THADA) with PCOS susceptibility and its related traits in Indian women. METHODS: We genotyped rs13429458 of THADA by direct sequencing and investigated its association with PCOS and its related traits in controls (N = 150) and PCOS women (N = 348). All women were extensively phenotyped in terms of anthropometric, hormonal and metabolic parameters. Association of polymorphism with PCOS risk and its related traits was carried out by regression analysis. RESULTS: Genotypic and allele frequencies for rs13429458 were not different between controls and PCOS. Women with PCOS carrying variant allele showed significantly reduced fasting glucose levels, and decreased free and bioavailable testosterone and free androgen index. CONCLUSION: To our knowledge, this is the first study to demonstrate that although this polymorphism does not alter PCOS susceptibility, it favorably impacts glucose metabolism and hyperandrogenism in Indian women with PCOS only. This study highlights that genetic predisposition markers for PCOS may differ with ethnicity and phenotypic variations.

Elucidating the impact of obesity on hormonal and metabolic perturbations in polycystic ovary syndrome phenotypes in Indian women.

Polycystic ovary syndrome is a complex endocrinopathy with heterogeneous presentation and multifactorial etiology. We have undertaken this case-control study to compare metabolic and endocrine characteristics in different phenotypic subgroups of women with PCOS and the impact of obesity on them. Women with PCOS (n = 489) were classified into 4 phenotypes according to Rotterdam criteria. Comparisons of clinical, biochemical and hormonal parameters were performed across all phenotypic groups of PCOS and with controls (n = 270) by Welch's ANOVA with subsequent Games-Howell post-hoc test. We found maximum prevalence of normoandrogenic phenotype D, which is milder form of PCOS in terms of insulin resistance, gonadotropin levels and dyslipidemia, followed by phenotype A, in our total study population. After classification of the study group into lean and obese groups, only few insulin and lipid-related traits showed marked differences between phenotypes. Further, we noted that obese women showed adverse metabolic but not androgenic traits compared to lean counterparts in the same phenotype. Metabolic syndrome frequency is increased in hyperandrogenic phenotypes with HDL-C and waist circumference being most predominant contributing factors in total, lean and obese groups. We demonstrate that in our study population there is greater occurrence of phenotype D of PCOS. Our study highlights the importance of clinicians concurrently employing Rotterdam criteria along with obesity status for ascertaining accurate PCOS status and formulating suitable therapeutic intervention.

PON1 promoter polymorphisms contribute to PCOS susceptibility and phenotypic outcomes in Indian women.

Polycystic ovary syndrome is a common endocrinopathy characterized by anovulatory infertility, hyperandrogenism, insulin resistance and oxidative stress, which predisposes affected women to reproductive and cardiometabolic complications in later life. We have investigated the association of PON1 promoter polymorphisms with PCOS susceptibility, PON1 activity and its related traits in Indian women. The genotypic and allelic frequency distribution of only -907G/C polymorphism in PON1 promoter showed significant difference between non-hyperandrogenic control and PCOS women, and was significantly associated with reduced susceptibility to PCOS, considering the recessive model. PON1 lactonase and arylesterase activities were also significantly decreased in women with PCOS compared to controls. Further, PON1 promoter polymorphisms were linked to altered insulin and testosterone levels in hyperandrogenic and non-hyperandrogenic women with PCOS. This study highlights PON1 as an important candidate gene influencing genetic pathophysiology of PCOS.

Pathomechanisms of polycystic ovary syndrome: Multidimensional approaches.

Polycystic ovary syndrome is a complex endocrine disorder affecting numerous women of reproductive age across the globe. Characterized mainly by irregular menses, hirsutism, skewed LH: FSH ratios and bulky polycystic ovaries, this multifactorial endocrinopathy results in unfavorable reproductive and metabolic sequelae, including anovulatory infertility, type 2 diabetes, metabolic syndrome and cardiovascular disease in later years. Increasing evidence has shown that the manifestation of polycystic ovary syndrome (PCOS) is attributable to a cumulative impact of altered genetic, epigenetic and protein profiles which bring about a systemic dysfunction. While genetic approaches help ascertain role of causal variants in its etiology, tissue-specific epigenetic patterns help in deciphering the auxiliary role of environmental, nutritional and behavioral factors. Proteomics is advantageous, linking both genotype and phenotype and contributing to biomarker discovery. Investigating molecular mechanism underlying PCOS is imperative in order to gain insight into the pathophysiology of PCOS and formulate novel diagnostic and treatment strategies. In this review we have summarized these three aspects, which have been successfully utilized to delineate the pathomechanisms of PCOS.

Polymorphisms and haplotypes of insulin-like factor 3 gene are associated with risk of polycystic ovary syndrome in Indian women.

BACKGROUND: Insulin-like factor 3 (INSL3), secreted by the ovarian theca cells is involved in androgen production, follicular growth and oocyte maturation. Both androgens and INSL3 levels are reported to be elevated in women with polycystic ovary syndrome (PCOS), indicating that INSL3 could contribute to PCOS etiology. This case-control association study explored the impact of INSL3 polymorphisms on PCOS susceptibility and its related traits. METHODS: Genotyping of exonic polymorphisms of INSL3 was performed in controls (n=333) and PCOS (n=405) women. Phenotyping (clinical, biochemical and hormonal parameters) was carried out in 205 controls and 301 PCOS women. Genotype, haplotype and genotype-phenotype associations were determined using statistical tests. RESULTS: Three polymorphisms in exon 1-rs2286663 (G/A), rs1047233 (A/G), and rs6523 (A/G), and one in exon 3-rs1003887 (G/A), were present in our study subjects. The frequencies of rs6523 and AGAG haplotype were significantly increased in PCOS women. The rs6523 polymorphism showed significant association with increased cholesterol and HDL-C levels in PCOS women while in controls with decreased FBS, Bio-T and FAI, and increased SHBG levels. Significant association of, rs1047233 polymorphism with improved androgen related parameters in controls, rs2286663 polymorphism with decreased QUICKI in PCOS and rs1003887 polymorphism with increased insulin levels and HOMA-IR in controls were observed. CONCLUSIONS: The rs6523 polymorphism and AGAG haplotype of INSL3 showed significant association with increased risk of PCOS. Additionally, INSL3 polymorphisms influenced metabolic and hyperandrogenemia related parameters in both controls and PCOS women. This is the first study to suggest that INSL3 may be a genetic predisposition factor in PCOS pathophysiology.

PON1 polymorphisms are associated with polycystic ovary syndrome susceptibility, related traits, and PON1 activity in Indian women with the syndrome.

OBJECTIVE: To investigate the association of paraoxonase 1 (PON1) polymorphisms (L55M and Q192R) with polycystic ovary syndrome (PCOS) susceptibility and its related traits in Indian women. DESIGN: Case-control study. SETTING: Academic research institute, infertility, and endocrinology clinics. PATIENT(S): Controls (n = 326), women with PCOS (n = 482). INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Genotypic and allelic frequency distribution, genotype-phenotype association, different PON1 activities (lactonase, arylesterase, and paraoxonase). RESULT(S): The genotypic and allelic frequency distributions of the L55M polymorphism were significantly different between lean controls and lean women with PCOS, and this polymorphism reduced the risk of PCOS development in lean but not in obese Indian women. Furthermore, this polymorphism was significantly associated with decreased 2-hour glucose, apolipoprotein B, free and bioavailable T, and free androgen index concurrent with increased sex hormone-binding globulin (SHBG) and FSH levels only in lean women with PCOS. However, Q192R polymorphism showed comparable genotypic frequency distribution between controls and women with PCOS. PON1 lactonase and arylesterase activities were significantly decreased in women with PCOS compared with controls. PON1 polymorphisms were shown to influence its activities. CONCLUSION(S): Our study showed that L55M, but not Q192R, polymorphism is significantly associated with reduced PCOS susceptibility only in lean women and also impacts glucose metabolism, lipid parameters, and hyperandrogenemia in them. Our study therefore suggests the possibility of differential genetic pathophysiology of PCOS between lean and obese women.