Association of SOD2 A16V and PON2 S311C polymorphisms with polycystic ovary syndrome in Chinese women

Genetic and Epigenetic Landscape for Drug Development in Polycystic Ovary Syndrome

The treatment of polycystic ovary syndrome (PCOS) faces challenges as all known treatments are merely symptomatic. The US Food and Drug Administration has not approved any drug specifically for treating PCOS. As the significance of genetics and epigenetics rises in drug development, their pivotal insights have greatly enhanced the efficacy and success of drug target discovery and validation, offering promise for guiding the advancement of PCOS treatments. In this context, we outline the genetic and epigenetic advancement in PCOS, which provide novel insights into the pathogenesis of this complex disease. We also delve into the prospective method for harnessing genetic and epigenetic strategies to identify potential drug targets and ensure target safety. Additionally, we shed light on the preliminary evidence and distinctive challenges associated with gene and epigenetic therapies in the context of PCOS.

Increased oxidative stress is associated with hyperandrogenemia in polycystic ovary syndrome evidenced by oxidized lipoproteins stimulating rat ovarian androgen synthesis in vitro

PURPOSE

To determine the relationship between serum total testosterone (TT) levels and oxidative stress indices in patients with polycystic ovary syndrome (PCOS), and to investigate the effect of oxidative stress on androgen synthesis and its mechanism in rat ovarian theca-interstitial (T-I) cells.

METHODS

Clinical, hormonal, metabolic, and oxidative stress parameters were analyzed in a cross-sectional case-control study including 626 patients with PCOS and 296 controls. The effects of oxidized low-density lipoprotein (ox-LDL) and oxidized high-density lipoprotein (ox-HDL) on cell proliferation, TT secretion, and expression of key enzymes involved in testosterone synthesis were evaluated in T-I cells.

RESULTS

Serum TT levels were elevated with an increase in ox-LDL levels, whereas glutathione concentrations were lower in the high-TT subgroup than in the low-TT subgroup. The average ovarian volume and ox-LDL and malondialdehyde levels were significant predictors of TT levels in the multivariate regression models. In a rat ovarian T-I cell model, lipoprotein and oxidized lipoprotein treatments stimulated proliferation and promoted testosterone secretion. The mRNA and protein levels of 17α-hydroxylase were significantly higher in oxidized lipoprotein-treated cells than those in lipoprotein-treated cells. The mRNA levels of cholesterol side chain cleavage enzyme and steroidogenic acute regulatory protein were also significantly higher in ox-HDL-treated cells than in HDL-treated cells.

CONCLUSIONS

Oxidative stress can promote androgen production by up-regulating the expression of testosterone synthesis-related enzymes in vitro and may be an essential factor in elevating serum TT levels in patients with PCOS.

Evidence for causal effects of polycystic ovary syndrome on oxidative stress: a two-sample mendelian randomisation study

BACKGROUND

Polycystic ovary syndrome (PCOS) is often accompanied by increased oxidative stress levels; however, it is still unclear whether PCOS itself is causally related to oxidative stress (OS), whether OS can increase the occurrence of PCOS, and which characteristics of PCOS increase OS levels. Therefore, this study explored the causal relationship between PCOS, its characteristics, and OS.

METHODS

Two-sample bidirectional and two-sample Mendelian randomisation studies were performed based on publicly available statistics from genome-wide association studies. PCOS; its characteristics, such as testosterone, low-density lipoprotein, high-density lipoprotein; and 11 major OS markers (superoxide dismutase, glutathione S-transferase, glutathione peroxidase, catalase, uric acid, zinc, tocopherol, ascorbic acid, retinol, albumin, and total bilirubin), were studied. The main analytical method used was inverse variance weighting (IVW). Pleiotropy was evaluated using the Mendelian randomisation-Egger intercept. Q and P values were used to assess heterogeneity.

RESULTS

There was no causal relationship between PCOS and the OS indices (all P > 0.05). There was a causal relationship between the OS index, ascorbate level, and PCOS (IVW, odds ratio: 2.112, 95% confidence interval: 1.257-3.549, P = 0.005). In addition, there was a causal relationship between testosterone, low-density lipoprotein, high-density lipoprotein, sex hormone-binding globulin, body mass index, triacylglycerol, age at menarche, and most OS indices according to the IVW method. The F statistics showed that there was no weak instrumental variable. A sensitivity analysis was performed using the leave-one-out method. No pleiotropy was observed. The results were robust, and the conclusions were reliable.

CONCLUSIONS

This study showed for the first time that there was no causal relationship between PCOS and OS. However, there was a causal relationship between the OS index, ascorbate level, and PCOS. It revealed that PCOS itself could not increase OS, and the increase in OS in PCOS was related to other potential factors, such as testosterone, low-density lipoprotein, high-density lipoprotein, sex hormone-binding globulin, body mass index, triacylglycerol, and age at menarche.

Association between CYP2E1 C-1054T and 96-bp I/D genetic variations and the risk of polycystic ovary syndrome in Chinese women

PURPOSE

To investigate the association of cytochrome P450 2E1 (CYP2E1) C-1054T (rs2031920) and 96-bp I/D genetic variations with the risk of polycystic ovary syndrome (PCOS), and to estimate the effects of genotypes on the clinical, metabolic, hormonal, and oxidative stress indicators.

METHODS

This case-control study included 762 control women and 1034 patients with PCOS. Genotypes were determined using polymerase chain reaction and/or restriction fragment length polymorphism analysis. Clinical and biochemical parameters were also analyzed.

RESULTS

Frequencies of the TT + CT genotype (35.4 vs. 28.9%) and T allele (19.6 vs. 16.0%) of the CYP2E1 C-1054T polymorphism were significantly higher in the PCOS group than in the control group (OR = 1.350, 95% CI 1.103-1.652, P = 0.004 for the dominant model). Genotype TT + CT remained a significant predictor of PCOS in a logistic regression model including age, body mass index (BMI), and recruitment year of participants (OR = 1.345, 95% CI 1.071-1.688, P = 0.011). No statistical differences were found in the genotype and allele frequencies of CYP2E1 96-bp I/D polymorphism. However, the combined genotype DD/TT + CT was related to an increased risk of PCOS when the DD/CC wild-type combined genotype was used as a reference. Patients with the I allele of 96-bp I/D polymorphism had a lower BMI but higher plasma apolipoprotein B and oxidized low-density lipoprotein cholesterol levels than those with the DD genotype.

CONCLUSION

CYP2E1 C-1054T, but not 96-bp I/D, genetic polymorphism is associated with an increased risk of PCOS in Chinese women.

The structure-function relationships and physiological roles of MnSOD mutants

In this review, we focus on understanding the structure–function relationships of numerous manganese superoxide dismutase (MnSOD) mutants to investigate the role that various amino acids play to maintain enzyme quaternary structure or the active site structure, catalytic potential and metal homeostasis in MnSOD, which is essential to maintain enzyme activity. We also observe how polymorphisms of MnSOD are linked to pathologies and how post-translational modifications affect the antioxidant properties of MnSOD. Understanding how modified forms of MnSOD may act as tumor promoters or suppressors by altering the redox status in the body, ultimately aid in generating novel therapies that exploit the therapeutic potential of mutant MnSODs or pave the way for the development of synthetic SOD mimics.

Association of CYBA C242T and superoxide dismutase 2 A16V genetic variants with preeclampsia

OBJECTIVE

To investigate the relationship between NADPH oxidase p22phox subunit (CYBA; C242T) and superoxide dismutase 2 (SOD2; A16V) polymorphisms and the risk of preeclampsia (PE) in Chinese women.

METHODS

This case-control study included 325 patients with PE and 1294 controls. The genotypes were determined by polymerase chain reaction-restriction fragments length polymorphism method. Clinical, metabolic, and oxidative stress parameters were analyzed.

RESULTS

Participants with T allele of the CYBA C242T polymorphism had a decreased risk of PE (OR = 0.62, 95% CI: 0.42-0.92, P = 0.016) and those with the A allele of the SOD2 A16V polymorphism had increased risk of PE (OR = 1.44, 95% CI: 1.09-1.89, P = 0.010). The coexistence of the SOD2 AA + AV genotypes and the CYBA CC genotype further increased the risk of PE (OR = 2.32, 95% CI: 1.31-4.10, P = 0.003) when the CT + TT/VV combined genotype was the reference category.

CONCLUSION

The T allele of the CYBA C242T polymorphism is related to a decreased risk of PE, while the A allele of the SOD2 A16V polymorphism and its combination with the CYBA CC genotype are associated with an increased risk of PE in Chinese women.

Association and Gene Polymorphisms with Polycystic Ovary Syndrome in Saudi Women

Polycystic ovary syndrome (PCOS) is a considered one of the most common female disorders associated with reproductive, metabolic, and psychological problems. The etiology of PCOS is still not yet disclosed; however, evidence for a genetic basis has been reported. In this study, we investigate the associations between superoxide dismutase 2 (<i>SOD2</i>) (rs4880) and paraoxonase 1 (<i>PON1</i>) (rs705379) polymorphisms in PCOS in Saudi women. The study included 99 females with PCOS and 98 healthy women as a control. Single nucleotide polymorphisms (SNPs) of promoter regions were determined using TaqMan genotyping assays. Regarding the polymorphism at <i>SOD2</i> (rs4880), the CC, CT, and TT genotypes were present at rates of 32, 61, and 7% in PCOS patients, and 47, 43, and 10% in controls, respectively. The frequency of the CT genotype in PCOS patients (0.61) was significantly higher than in controls (0.43) (OR = 2.05, CI: 1.16–3.61; <i>p</i> = 0.015). The wild homozygous genotype (CC) with the phenotype alanine appears to confer protection against the disease compared to molecules sharing at least one valine (genotypes, CT + TT). Regarding the polymorphism at <i>PON1</i> (rs705379), the rates of CC, CT, and TT genotypes were 34, 50, and 16% in PCOS patients and 33, 63, and 2% in controls, respectively. The rate of the TT genotype in PCOS patients was significantly higher than that in controls (<i>p</i> = 0.0058). <i>SOD2</i> and <i>PON1</i> polymorphisms may be genetic factors that affect the occurrence of PCOS in Saudi females.

Association of Polymorphisms of Glutamate Cysteine Ligase Genes GCLC C-129 T and GCLM C-588 T with Risk of Polycystic Ovary Syndrome in Chinese Women

Polycystic ovary syndrome (PCOS) is generally considered a multifactorial disease caused by interactions between multiple susceptible genes and environmental factors. Glutamate cysteine ligase (GCL) is the rate-limiting enzyme in glutathione biosynthesis. This study examined the relationship between single nucleotide polymorphisms (SNPs) in the GCL catalytic subunit (GCLC C-129 T) and the modifier subunit (GCLM C-588 T) and PCOS. The two SNPs were genotyped in 1017 PCOS patients and 793 control women. Clinical, metabolic, hormonal, and oxidative stress parameters were also assessed. The frequencies of the CT + TT genotypes (21.6% vs. 27.7%) and T allele (11.5% vs. 14.7%) of SNP GCLC C-129 T were significantly lower in hyperandrogenism (HA)-PCOS patients than in control women. Logistic regression analysis revealed that the relative hazard of HA-PCOS was lower in individuals with the -129 T allele (CT + TT genotypes) than in those with the CC genotype (OR = 0.723, 95% CI: 0.571-0.915, P = 0.007). When using the GCLC-CC/GCLM-CC combined genotype as the reference category, the GCLC-CT + TT/GCLM-CC combined genotype was a protective factor for PCOS with HA (OR = 0.743, 95% CI: 0.566-0.976, P = 0.033). HA-PCOS patients with the -129 T allele had lower waist circumference, waist-to-hip ratio, and body mass index (BMI) and lower fasting insulin concentration and homeostatic model assessment of insulin resistance after correcting for age and BMI (P < 0.05). The T allele of SNP GCLC C-129 T and its combination with the CC genotype of SNP GCLM C-588 T are associated with decreased risk of HA-PCOS in Chinese women.

Oxidative stress promotes hyperandrogenism by reducing sex hormone-binding globulin in polycystic ovary syndrome

OBJECTIVE

To determine the relationships between circulating sex hormone-binding globulin (SHBG) and oxidized low-density lipoprotein (ox-LDL), total oxidant status, total antioxidant capacity, oxidative stress index, malondialdehyde, and the high-density lipoprotein (HDL) inflammatory index in patients with polycystic ovary syndrome (PCOS) and to investigate the effect of oxidative stress on the expression of SHBG and its mechanism in HepG2 cells.

DESIGN

Cross-sectional study.

SETTING

University hospital.

PATIENT(S)

A total of 533 women with PCOS and 292 control women were included.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Circulating SHBG, hormones, and metabolic and oxidative stress indices were determined in all subjects. The effects of ox-LDL and ox-HDL on the mRNA and protein expression of SHBG and related transcription factors were observed in HepG2 cells.

RESULT(S)

The HDL inflammatory index, total oxidant status, oxidative stress index, and malondialdehyde levels were significantly higher in the three PCOS subgroups with different SHBG levels than in the controls. The ox-LDL and total antioxidant capacity were higher in the PCOS subgroups with SHBG levels <75th percentile compared with the controls or the PCOS subgroup with SHBG levels ≥75th percentile. In HepG2 cells, the SHBG concentration in the culture supernatant, the mRNA levels of SHBG and hepatocyte nuclear factor-4α (HNF-4α), and the protein levels of HNF-4α were significantly lower in ox-LDL- and ox-HDL-treated cells than in the control cells and lipoprotein-treated cells.

CONCLUSION(S)

Oxidative stress inhibits the expression and secretion of SHBG by downregulating HNF-4α in vitro and may be an important factor promoting the occurrence of hyperandrogenemia in PCOS.

Paraoxonase single nucleotide variants show associations with polycystic ovary syndrome: a meta-analysis

BACKGROUND

Etiology of polycystic ovary syndrome (PCOS) is attributed to genetic and environmental factors. One environmental factor is oxidative stress. Paraoxonase 1 (PON1) is an antioxidant high-density lipoprotein-associated enzyme encoded by the PON1 gene. The PON1 gene has been implicated in the risk for PCOS, the influence of which appears to come from single nucleotide variants (SNVs) at multiple genetic loci. However, association study reports have been inconsistent which compels a meta-analysis to obtain more precise estimates.

METHODS

From 12 publications, extracted genotype data were used in two genetic procedures. First, linkage disequilibrium (LD) was used to group eight PON SNVs into three: LD1, LD2 and LD3. Second, frequencies of the variant (var), wild-type (wt) and heterozygous (het) genotypes were used for genetic modeling (allele-genotype for LD1 and standard for LD2 and LD3). Risk associations were expressed in terms of pooled odds ratios (ORs), 95% confidence intervals (CIs) and P^a-values. Evidence was considered strong when significance was high (P^a < 0.0001) and heterogeneity absent (I² = 0%). Pooled effects were subjected to modifier (power), subgroup (Asian/Caucasian), outlier, sensitivity and publication bias treatments. Multiple comparisons were Bonferroni-corrected.

RESULTS

This meta-analysis generated 11 significant outcomes, five in LD1, six in LD2 and none in LD3. All six LD2 outcomes did not survive the Bonferroni-correction but two of the five in LD1 did. These two core LD1 findings conferred greater odds of PCOS to the var allele in the highly significant (P^a < 0.0001) overall (OR 1.44, 95% CI 1.24-1.67) and Asian (OR 1.41, 95% CI 1.20-1.65) outcomes. Of these two core outcomes, the Asian effect was homogeneous (I² = 0%) but not the overall (I² = 29%).

CONCLUSIONS

Of the eight PON SNVs examined, two (rs854560 and rs662) were associated with PCOS risk. These 1.4-fold increased risk effects rendered Asians susceptible to PCOS. High statistical power, high significance, zero to low-level heterogeneity, robustness and lack of bias in the core outcomes underpinned the strong evidence for association.

Riding the tiger - physiological and pathological effects of superoxide and hydrogen peroxide generated in the mitochondrial matrix

Elevated mitochondrial matrix superoxide and/or hydrogen peroxide concentrations drive a wide range of physiological responses and pathologies. Concentrations of superoxide and hydrogen peroxide in the mitochondrial matrix are set mainly by rates of production, the activities of superoxide dismutase-2 (SOD2) and peroxiredoxin-3 (PRDX3), and by diffusion of hydrogen peroxide to the cytosol. These considerations can be used to generate criteria for assessing whether changes in matrix superoxide or hydrogen peroxide are both necessary and sufficient to drive redox signaling and pathology: is a phenotype affected by suppressing superoxide and hydrogen peroxide production; by manipulating the levels of SOD2, PRDX3 or mitochondria-targeted catalase; and by adding mitochondria-targeted SOD/catalase mimetics or mitochondria-targeted antioxidants? Is the pathology associated with variants in SOD2 and PRDX3 genes? Filtering the large literature on mitochondrial redox signaling using these criteria highlights considerable evidence that mitochondrial superoxide and hydrogen peroxide drive physiological responses involved in cellular stress management, including apoptosis, autophagy, propagation of endoplasmic reticulum stress, cellular senescence, HIF1α signaling, and immune responses. They also affect cell proliferation, migration, differentiation, and the cell cycle. Filtering the huge literature on pathologies highlights strong experimental evidence that 30-40 pathologies may be driven by mitochondrial matrix superoxide or hydrogen peroxide. These can be grouped into overlapping and interacting categories: metabolic, cardiovascular, inflammatory, and neurological diseases; cancer; ischemia/reperfusion injury; aging and its diseases; external insults, and genetic diseases. Understanding the involvement of mitochondrial matrix superoxide and hydrogen peroxide concentrations in these diseases can facilitate the rational development of appropriate therapies.

Genetic Variability in Antioxidative and Inflammatory Pathways Modifies the Risk for PCOS and Influences Metabolic Profile of the Syndrome

Polycystic ovary syndrome (PCOS) is a complex endocrine and metabolic disorder of multifactorial etiopathology likely to involve the interactions between genetics and lifestyle. Chronic inflammation and oxidative stress (OS) may participate in the pathophysiology of the syndrome. The question of the extent to which OS and inflammation are causally related to the development of the syndrome and metabolic complications remains unanswered. By our knowledge, the role of the NLR family pyrin domain containing 3 (NLRP3) inflammasome as an important trigger of inflammatory pathways and NLRP3 and CARD8 polymorphisms has never been addressed in PCOS yet. We conducted a case-control study conducting of total 169 Slovenian PCOS patients and 83 healthy blood donors. They were genotyped for polymorphisms in antioxidative (SOD2 rs4880, CAT rs1001179, PON1 rs854560, and rs662) and inflammatory pathways genes (NLRP3 rs35829419, CARD8 rs2043211, TNF rs1800629, IL1B rs1143623, and rs16944, IL6 rs1800795) using competitive allele-specific polymerase chain reaction (PCR). Logistic regression and the Mann–Whitney test were used in the statistical analysis. SOD2 rs4880, CARD8 rs2043211, and IL1B rs16944 were associated with the risk of developing PCOS. Furthermore, the interactions between CARD8 rs2043211 and IL6 rs1800795 and between IL1B rs1143623 and IL6 rs1800795 also significantly affected the risk for PCOS. With regard to glucose homeostasis, CAT rs1001179, SOD2 rs4880, PON1 rs854560, NLRP3 rs35829419, and TNF rs1800629 were significantly associated with response to the glycemic load. Our data indicate that the genetic variability in the antioxidative and inflammatory pathways influences the development of PCOS and glucose homeostasis in PCOS patients.

A genome-wide association study of polycystic ovary syndrome identified from electronic health records

BACKGROUND

Polycystic ovary syndrome is the most common endocrine disorder affecting women of reproductive age. A number of criteria have been developed for clinical diagnosis of polycystic ovary syndrome, with the Rotterdam criteria being the most inclusive. Evidence suggests that polycystic ovary syndrome is significantly heritable, and previous studies have identified genetic variants associated with polycystic ovary syndrome diagnosed using different criteria. The widely adopted electronic health record system provides an opportunity to identify patients with polycystic ovary syndrome using the Rotterdam criteria for genetic studies.

OBJECTIVE

To identify novel associated genetic variants under the same phenotype definition, we extracted polycystic ovary syndrome cases and unaffected controls based on the Rotterdam criteria from the electronic health records and performed a discovery-validation genome-wide association study.

STUDY DESIGN

We developed a polycystic ovary syndrome phenotyping algorithm on the basis of the Rotterdam criteria and applied it to 3 electronic health record-linked biobanks to identify cases and controls for genetic study. In the discovery phase, we performed an individual genome-wide association study using the Geisinger MyCode and the Electronic Medical Records and Genomics cohorts, which were then meta-analyzed. We attempted validation of the significant association loci (P<1×10^-6) in the BioVU cohort. All association analyses used logistic regression, assuming an additive genetic model, and adjusted for principal components to control for population stratification. An inverse-variance fixed-effect model was adopted for meta-analysis. In addition, we examined the top variants to evaluate their associations with each criterion in the phenotyping algorithm. We used the STRING database to characterize protein-protein interaction network.

RESULTS

Using the same algorithm based on the Rotterdam criteria, we identified 2995 patients with polycystic ovary syndrome and 53,599 population controls in total (2742 cases and 51,438 controls from the discovery phase; 253 cases and 2161 controls in the validation phase). We identified 1 novel genome-wide significant variant rs17186366 (odds ratio [OR]=1.37 [1.23, 1.54], P=2.8×10^-8) located near SOD2. In addition, 2 loci with suggestive association were also identified: rs113168128 (OR=1.72 [1.42, 2.10], P=5.2×10^-8), an intronic variant of ERBB4 that is independent from the previously published variants, and rs144248326 (OR=2.13 [1.52, 2.86], P=8.45×10^-7), a novel intronic variant in WWTR1. In the further association tests of the top 3 single-nucleotide polymorphisms with each criterion in the polycystic ovary syndrome algorithm, we found that rs17186366 (SOD2) was associated with polycystic ovaries and hyperandrogenism, whereas rs11316812 (ERBB4) and rs144248326 (WWTR1) were mainly associated with oligomenorrhea or infertility. We also validated the previously reported association with DENND1A1. Using the STRING database to characterize protein-protein interactions, we found both ERBB4 and WWTR1 can interact with YAP1, which has been previously associated with polycystic ovary syndrome.

CONCLUSION

Through a discovery-validation genome-wide association study on polycystic ovary syndrome identified from electronic health records using an algorithm based on Rotterdam criteria, we identified and validated a novel genome-wide significant association with a variant near SOD2. We also identified a novel independent variant within ERBB4 and a suggestive association with WWTR1. With previously identified polycystic ovary syndrome gene YAP1, the ERBB4-YAP1-WWTR1 network suggests involvement of the epidermal growth factor receptor and the Hippo pathway in the multifactorial etiology of polycystic ovary syndrome.

Five variants of the superoxide dismutase genes in Turkish women with polycystic ovary syndrome

INTRODUCTION

Polycystic ovary syndrome (PCOS) is one of the most common endocrine-reproductive-metabolic disorders of women at reproductive age. Many investigations have revealed that reactive oxygen species (ROS) level is significantly increased in patients with PCOS compared to healthy women.

OBJECT

The goal of the current study is to investigate the association between superoxide dismutase (SOD) variants and the risk of PCOS among Turkish women.

METHOD AND SUBJECTS

Three hundred twelve voluntary premenopausal women (148 healthy controls and 164 patients with PCOS) 18-45 years of age were include the study. All volunteers underwent physical examination and biochemical hormones evaluation. Five selected variants in SOD1 (+35 A/C (rs2234694) and SOD2 (-102 C > T, 3'UTRT > A (rs2842980), 3'UTRA > G (rs5746136), and Ala16ValC > T (rs4880) were analysed by using polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) method.

RESULT

3'UTRA > G and Ala16ValC > T variants showed significant differences between study groups. In the additive model of rs5746136 variant having AG and GG genotype increased the PCOS risk 2-fold (OR: 1.7, 95% CI: 1.08-2.77, p = 0.003) and 5-fold (OR: 5, 95% CI: 1.7-14.2,p = 0.003) compared to AA genotype, respectively. To have a GG + AG genotype increased the PCOS risk 2-fold (OR: 2.95% Cl: 1.2-3.1, p = 0.003) compared to AA genotype in "G" dominant model. In case of the "G" recessive model, having a GG genotype increased the PCOS risk 4-fold (OR: 3.8, 95% CI: 1.3-10.4, p = 0.01) compared to AA + AG genotype. The TT genotype of rs4880 showed almost 2-fold (OR: 1.8, 95% CI: 1.12-3.0) increased PCOS risk in the "T" recessive model.

CONCLUSION

It is quite likely that the variants which result in decreased function in the antioxidant defence mechanism related genes contribute to PCOS aetiology with inhibiting/reducing of ROS elimination.

Association of the Genetic Polymorphisms rs6259 and rs727428 of the SHBG Gene with Polycystic Ovary Syndrome Risk: A Meta-Analysis

Background: Studies investigating the relationship between polymorphisms of the sex hormone-binding globulin (SHBG) gene and polycystic ovary syndrome (PCOS) have reported differing results. Therefore, the present meta-analysis was performed to clarify the effects of the SHBG rs6259 and rs727428 polymorphisms on PCOS risk. Materials and Methods: Published English language studies were selected through an extensive search of the Web of Science, PubMed, and EMBASE databases. Chinese studies were identified using Wan Fang, VIP, and the Chinese National Knowledge Infrastructure (CNKI) databases. The pooled odds ratio and 95% confidence interval were calculated using the random-effects model. Subgroup analyses and heterogeneity analyses were also performed. Results: A total of 1660 cases and 1312 controls were included in this meta-analysis. We found that the SHBG rs6259 polymorphism was not significantly associated with an increased risk of PCOS in any of the genetic models with significant heterogeneity; the results were consistent for all subgroups. A nonsignificant association between the rs727428 polymorphism and an increased risk of PCOS was also detected in all genetic models. Conclusions: The findings of this meta-analysis suggest that neither the SHBG rs6259 nor rs727428 polymorphism are associated with susceptibility to PCOS. However, because of the considerable heterogeneity and the small sample size, these pooled results should be interpreted with caution.

Association of GPx1 P198L and CAT C-262T Genetic Variations With Polycystic Ovary Syndrome in Chinese Women

Background: Oxidative stress plays an important role in the pathogenesis of polycystic ovary syndrome (PCOS). Glutathione peroxidase 1 (GPx1) and catalase (CAT) are the major intracellular antioxidant enzymes that can detoxify hydrogen peroxide into water, preventing cellular injury from reactive oxygen species. The aim of the present study was to investigate the association of GPx1 P198L (Pro198Leu, C559T, rs1050450) and CAT C-262T (rs1001179) genetic polymorphisms with the risk of PCOS and evaluate the effects of the genotypes on clinical, hormonal, metabolic and oxidative stress parameters in Chinese women. Methods: This is a case-control study of 654 patients with PCOS and 535 controls. The GPx1 P198L, CAT C-262T, and superoxide dismutase 2 (SOD2) A16V genotypes were determined by polymerase chain reaction amplification and restriction analysis. Clinical, hormonal, metabolic and oxidative stress parameters were also analyzed. Results: The frequencies of the PL + LL genotype (14.1 vs. 8.4%) and L allele (7.3 vs. 4.4%) of GPx1 P198L polymorphism were significantly higher in patients with PCOS than in control subjects. Genotype (PL + LL) remained a significant predictor for PCOS in prognostic models including age, body mass index (BMI), insulin resistance index, total cholesterol, triglycerides, high-density lipoprotein-cholesterol, and low-density lipoprotein-cholesterol as covariates (OR = 2.105, 95%CI: 1.330-3.331, P = 0.001). Patients carrying the L allele had relatively high average ovarian volume, waist circumference, and malondialdehyde levels (P < 0.07) compared with patients with the PP genotype. We also demonstrated that the subjects with both GPx1 L and SOD2 A alleles further increase the risk of PCOS compared with the individuals carrying the PP/VV genotype after adjusting for age and BMI (OR = 5.774, 95%CI: 2.243-14.863, P < 0.001). However, no significant differences were observed in the frequencies of the CAT C-262T genotypes and alleles between PCOS and control groups. Conclusions: The GPx1 P198L, but not CAT C-262T, genetic polymorphism is associated with the risk of PCOS in Chinese women.