Vitamin D receptor gene polymorphisms and risk of polycystic ovary syndrome in South Indian women

Genetic association of vitamin D receptor gene with female infertility

BACKGROUND

Infertility is defined as failure to achieve a clinical pregnancy after 12 months of unprotected intercourse. It affects 15% of couples globally and 22% of couples within Pakistan. Female infertility can be caused by numerous genetic or environmental factors including hormone imbalances and exposure to chemicals or radiation. The prevalence of vitamin D deficiency among the adult population was reported to be 14-59% with a higher prevalence in Asian countries. Furthermore, the expression of Vitamin D receptor (VDR) can play a vital role in the reproductive organs of females. Hence, the aim of our present study was to check the association of VDR polymorphisms with infertile females. For this purpose, blood samples were collected for genotyping of four known VDR mutations [FokI (rs2228570), TaqI (rs731236), ApaI (rs7975232), and BsmI (rs1544410)] via PCR-based RFLP assay.

RESULTS

Genotyping indicated that FokI, TaqI, and ApaI are associated with infertility (p = 0.004*, p = 0.013*, and p = 0.033*, respectively). However, BsmI did not show any significance. Multinomial regression analysis indicated that FokI heterozygous genotypes increase the risk of infertility by 2.5 times (hetero: OR = 2.5, 95%, p = 0.001*) as compared to wild type. Heterozygous genotypes of TaqI and ApaI were found to play a protective role and reduce the risk of infertility by 58 and 52%, respectively [TaqI: OR = 0.42, 95%, p = 0.004*, ApaI: OR = 0.48, 95%, p = 0.01*, respectively] as compared to wild type. Multinomial logistic regression analysis was also performed for allelic data as well.

CONCLUSION

Thus, it could be summarized that among the studied polymorphisms of VDR, FokI SNP greatly increased the risk of infertility, while TaqI and ApaI genotypes protect from infertility. However, BsmI does not influence the risk of infertility in Pakistani females.

Multi-omics insights and therapeutic implications in polycystic ovary syndrome: a review

Polycystic ovary syndrome (PCOS) is a common gynecological disease that causes adverse effects in women in their reproductive phase. Nonetheless, the molecular mechanisms remain unclear. Over the last decade, sequencing and omics approaches have advanced at an increased pace. Omics initiatives have come to the forefront of biomedical research by presenting the significance of biological functions and processes. Thus, multi-omics profiling has yielded important insights into understanding the biology of PCOS by identifying potential biomarkers and therapeutic targets. Multi-omics platforms provide high-throughput data to leverage the molecular mechanisms and pathways involving genetic alteration, epigenetic regulation, transcriptional regulation, protein interaction, and metabolic alterations in PCOS. The purpose of this review is to outline the prospects of multi-omics technologies in PCOS research by revealing novel biomarkers and therapeutic targets. Finally, we address the knowledge gaps and emerging treatment strategies for the management of PCOS. Future PCOS research in multi-omics at the single-cell level may enhance diagnostic and treatment options.

Histone deacetylase 1, Sirtuin 1, and Sirtuin 3 single-nucleotide polymorphisms and the risk of endometriosis in South Indian women

The aim of the study was to investigate the association between Histone deacetylase 1 (HDAC1), Sirtuin1 (SIRT1), and Sirtuin3 (SIRT3) single-nucleotide polymorphisms (SNPs) and risk of endometriosis in South Indian women. A total of 300 subjects were recruited in this case-control study comprising 150 affected women and 150 women with no evidence of disease. All the subjects were of South Indian origin. The genotyping of HDAC1, SIRT1, and SIRT3 SNPs (rs1741981T/C, rs144124002A/G, and rs536715G/A) was carried out on DNA from subjects by PCR-RFLP and sequencing analysis. The genotype (p = .00782) and allele (p = .02561) frequencies of the HDAC1 rs1741981 polymorphism showed significant difference between cases and controls. In contrast, SIRT1 (rs144124002) and SIRT3 (rs536715) SNPs did not show significant association with the disease. The HDAC1 polymorphism may constitute a heritable risk factor for endometriosis in South Indian women. To date, there is no reported study on the association of polymorphisms in HDAC1, SIRT1, and SIRT3 with endometriosis risk. Impact StatementWhat is already known on this subject? Endometriosis is a benign gynaecological disease characterised by the implantation of functional endometrial tissue at ectopic positions, associated with an increased risk of malignant transformation. Epigenetic mechanisms are essential for normal development and maintenance of tissue-specific gene expression patterns. Histone modification, including deacetylation of lysine residues by HDACs, is a key epigenetic mechanism of gene expression regulation in endometriosis, therefore genetic variation in HDACs causing epigenetic control defects might lead to disease susceptibility.What do the results of this study add? Our study shows that the HDAC1 SNP is significantly associated with endometriosis in South Indian women, whereas the SNPs of SIRT1 and SIRT3 could not show any association with the disease.What are the implications of these findings for clinical practice and/or further research? The polymorphism of HDAC1 rs1741981 could be used as an important marker of genetic susceptibility to endometriosis development. Analysis of this SNP might help to identify patients at high risk for disease outcome.

Polymorphisms of Vitamin D Receptor and the Effect on Metabolic and Endocrine Abnormalities in Polycystic Ovary Syndrome: A Review

Polycystic ovary syndrome (PCOS) is one of the most prevalent endocrine disorder in women of reproductive age. Vitamin D and its receptor are thought to play an important role in PCOS susceptibility, although the impact of vitamin D receptor (VDR) polymorphisms on the hormonal and metabolic profile is still controversial. A literature search in PubMed and Embase was performed up to September 2020 for case-control studies in women suffering from PCOS, with outcome related to VDR polymorphisms effect on metabolic/endocrine disturbances. We have found 16 eligible studies including 2566 women with PCOS and 2430 controls. ApaI polymorphism seemed to be associated with hyperandrogenism in both Asian and Caucasian population. FokI variant was correlated with metabolic/endocrine parameters especially in Asian population, while a relation between Cdx2 genotypes and insulin sensitivity was observed in both ethnicities. VDR polymorphisms have an important role in PCOS development and related hormonal and metabolic abnormalities. Few case-control studies analysed the interaction between VDR variants and metabolic/endocrine parameters with the majority of the articles focused on the Asian region. Further research on various ethnic populations with larger sample size are still needed for a definitive conclusion, in order to allow early diagnosis and prevention of PCOS comorbidities.

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.

Pathogenetic analysis of polycystic ovary syndrome from the perspective of omics

Polycystic ovary syndrome (PCOS) is the most common gynecological endocrine disease, involving multiple genes, multiple pathways, and complex hormone secretion processes. Hence, the pathogenesis of PCOS cannot be explained by a single factor. Omics analysis includes genomics, transcriptomics, and proteomics, which are fast and effective methods for studying the pathogenesis of diseases. PCOS is primarily characterized by androgen excess, and reproductive and metabolic dysfunctions. The application of omics analysis in the body fluids, blood, cells or tissues of women with PCOS offers the potential for unexpected molecular advantages in explaining new mechanisms of PCOS etiology and pathophysiology, and provides new perspectives for identifying potential biomarkers and developing new therapeutic targets. At present, several omics analyses have been applied to produce complex datasets. In this manuscript, the recent advances in omics research on PCOS are summarized, aiming at an important and parallel review of the newly published research.

Association between melatonin receptor gene polymorphisms and polycystic ovarian syndrome: a systematic review and meta-analysis

BACKGROUND

Polycystic ovarian syndrome (PCOS) is a kind of common gynecological endocrine disorder. And the mutations of melatonin receptor (MTNR) genes are related to the occurrence of PCOS. But previous researches have shown opposite results. So, the object of our systematic review and meta-analysis is to investigate the relationship between MTNR 1A/B polymorphisms and PCOS.

METHODS

PubMed, Embase, Ovid, the Cochrane Library, Web of Science and three Chinese databases (VIP, CNKI and Wanfang) were used to retrieve eligible articles published between January 1980 and February 2020. And we used the odds ratio (OR) and its 95% confidence interval (CI) to investigate the strength of the association by six genetic models, allelic, codominant (homozygous and heterozygous), dominant, recessive and superdominant models. Review Manager 5.3, IBM SPSS statistics 25 and Stata MP 16.0 software were used to do this meta-analysis.

RESULTS

Our meta-analysis involved 2553 PCOS patients and 3152 controls, for two single nucleotide polymorphisms (rs10830963 C> G in MTNR1B and rs2119882 T> C in MTNR1A) and significant associations were found in some genetic models of these single nucleotide polymorphisms (SNPs). For rs10830963, strongly significant was found in the heterozygote model (GC vs. CC, P=0.02). Additionally, a slight trend was detected in the allelic (G vs. C), homozygote (GG vs. CC) and dominant (GG+GC vs. CC) model of rs10830963 (P=0.05). And after further sensitivity analysis, a study with high heterogeneity was removed. In the allelic (P=0.000), homozygote (P=0.001), dominant (P=0.000) and recessive (GG vs. GC+CC, P=0.001) model, strong associations between rs10830963 and PCOS were found. Moreover, for rs2119882, five genetic models, allelic (C vs. T, P=0.000), codominant (the homozygote (CC vs. TT, P=0.000) and heterozygote model (CT vs. TT, P=0.02), dominant (CC + CT vs. TT, P=0.03) and recessive model (CC vs. CT + TT, P=0.000) showed significant statistical associations with PCOS.

CONCLUSION

MTNR1B rs10830963 and MTNR1B rs2119882 polymorphisms are associated with PCOS risk. However, the above conclusions still require being confirmed by much larger multi-ethnic studies.

Genetic polymorphisms associated with polycystic ovary syndrome among Iranian women

Polycystic ovary syndrome (PCOS) involves abnormalities in ovarian, reproductive, and metabolic systems. Genetic polymorphisms associated with individual differences and variations might be related to complex disorders with unknown causes, including PCOS. Several leading genetic markers with known cellular functions have been identified among Iranian women presenting with PCOS. In particular, the existing evidence shows a significant relationship between PCOS and the following genetic polymorphisms: rs2275913 (interleukin-17A), rs9927163 (interleukin-32), Pro12Ala (peroxisome proliferator-activated receptor-γ), rs17173608 (chemerin), rs2236242 (vaspin), ApaI (vitamin D receptor), and rs7895833 (sirtuin 1). In addition, a higher risk of PCOS is associated with the rs2910164 (microRNA 146a), rs2241766 (adiponectin), -34 T/C (cytochrome 17), and rs1800682 (Fas) polymorphisms. Furthermore, protective effects against PCOS have been reported for the A4223C polymorphism of adenosine deaminase 1. Overall, the available data indicate that Iranian women with PCOS have a higher prevalence of polymorphisms in inflammation- and metabolism-related genes, but not in insulin-related genes. More extensive studies are needed to identify the ethnicity-related genetic associations in PCOS.

Association of BsmI variant of vitamin D receptor gene with polycystic ovary syndrome: A case-control study

Background

Polycystic ovarian syndrome (PCOS) is an endocrine disorder that affects women's fertility and causes alterations such as obesity, insulin resistance, menstrual irregularities, and polycystic ovaries. The results of the studies show that the issue of vitamin D and vitamin D receptor (VDR) is controversial for PCOS susceptibility.

Objective

To investigate the association of BsmI polymorphism in the VDR gene with metabolic parameters in obese PCOS women.

Materials and Methods

In this case-control study, 38 obese subjects with PCOS and 40 unrelated obese individuals were evaluated to determine the allelic and genotypic frequency of BsmI variant by Polymerase Chain Reaction Restriction Fragment Length Polymorphism method. Body Mass Index, parathyroid hormone, phosphorus, and calcium were evaluated in all participants.

Results

BsmI (rs1544410), (A/G) AA, AG, GG, A, and G percentage of genotypic/allelic frequencies were 65.8, 26.3, 7.9, 78.9, and 21.1 in cases and 57.5, 40, 2.5, 77.5, and 22.5 in controls, respectively. Statistical analysis revealed that the differences in genotypic (p = 0.31)/allelic (p = 0.83) frequencies and dominant (p = 0.45)/recessive (p = 0.35) models between the cases and controls were not significant. This study indicates no association between the BsmI genotypes and metabolic parameters.

Conclusion

It can be concluded that VDR BsmI (rs1544410) Intron 8 (A > G) was not associated with obesity along with PCOS susceptibility in the studied groups.

Association of genetic variations in phosphatase and tensin homolog (PTEN) gene with polycystic ovary syndrome in South Indian women: a case control study

PURPOSE

The purpose of the study was to investigate the association between gene phosphate and tensin homolog (PTEN) single nucleotide polymorphisms (SNPs) and risk of developing polycystic ovary syndrome (PCOS) in South Indian women. PTEN is one of the most important tumor suppressor genes that regulate cell proliferation, migration, and death. It is also involved in the maintenance of genome stability. PCOS is one of the most common endocrine disorders among women of reproductive age. It is a heterogeneous syndrome characterized by abnormal reproductive cycles, irregular ovulation, hormonal imbalance, hyperandrogenism, acne and hirsutism.

RESEARCH QUESTION

What is the association status of PTEN SNPs with PCOS?

METHODS

A total of 240 subjects were recruited in this case-control study comprising 110 patients with PCOS and 130 individuals without PCOS. All the subjects were of South Indian origin. The genotyping of PTEN SNPs (rs1903858 A/G, rs185262832G/A and rs10490920T/C) was carried out on DNA from subjects by polymerase chain reaction (PCR) and sequencing analysis. Haplotype frequencies for multiple loci and the standardized disequilibrium coefficient (D') for pairwise linkage disequilibrium (LD) were surveyed by Haploview Software.

RESULTS

Our results showed significant increase in the frequencies of rs1903858 A/G (P = 0.0016), rs185262832 G/A (P = 0.0122) and rs10490920 T/C (P = 0.0234) genotypes and alleles in cases compared to controls.

CONCLUSION

The PTEN (rs1903858A/G, rs185262832G/A and rs10490920T/C) gene polymorphisms may constitute an inheritable risk factor for PCOS in South Indian women.

Vitamin D receptor and binding protein polymorphisms in women with polycystic ovary syndrome: a case control study

BACKGROUND

Polycystic ovary syndrome (PCOS) is the most common endocrinopathy in women of reproductive age, characterized by hyperandrogenism, oligomenorrhea, polycystic ovary morphology, and insulin resistance. Vitamin D deficiency and vitamin D receptor (VDR)/vitamin D binding protein (VDBP) gene variants could play an important role in susceptibility to PCOS and contribute to metabolic disturbances and menstrual dysfunction. We aimed to investigate the associations of VDR gene and VDBP gene polymorphisms with PCOS susceptibility and to elucidate the impacts of these polymorphisms on the hormonal and metabolic parameters of PCOS.

METHODS

We recruited 432 women with PCOS and 927 controls. Polymorphisms in the VDR gene (VDR Fok-I, Cdx2, Apa-I, and Bsm-I) and VDBP gene (VDBP rs4588, rs7041, and rs22822679) were genotyped. A 75-g oral glucose tolerance test was performed.

RESULTS

The distributions of genotypes and allele frequencies in VDR and VDBP genes did not differ between PCOS and control. In women with PCOS, compared to the VDR Fok-I GG genotype, the VDR Fok-I AG genotype was significantly associated with increased levels of total testosterone (β = 5.537, P = 0.005). Compared to the VDR Cdx2 AC genotype, the VDR Cdx2 CC genotype was associated with increased levels of fasting insulin and HOMA-IR in women with PCOS, however, the associations were not statistically significant.

CONCLUSIONS

This finding indicates that genetic variations in VDR and VDBP were not associated with increased risk for PCOS. In contrast, the VDR Fok-I polymorphism was associated with testosterone level and the Cdx2 polymorphism with insulin sensitivity in PCOS. However, the Cdx2 polymorphism was not significantly associated with increased insulin and insulin sensitivity in women with PCOS after multiple linear regression.

Association of vitamin D receptor gene variants with polycystic ovary syndrome: a meta-analysis

BACKGROUND

Polycystic ovary syndrome (PCOS) is a common endocrine disorder in reproductive-age women. Multiple susceptible gene as well as environmental factors and their interaction each other are contributed to the PCOS risk. Several case-control studies have researched the associations of the vitamin D receptor gene (VDR) polymorphisms with PCOS susceptibility, but the jury is still out. Here, we carried out a meta-analysis to clarify polymorphisms between ApaI (C/A) (rs7975232), BsmI (G/A) (rs1544410), FokI (C/T) (rs10735810), TaqI (T/C) (rs731236) and Tru9I (G/A) (rs757343) in the VDR gene and PCOS susceptibility based on relative lager sample size.

METHODS

English database of PubMed and Embase, and Chinese database of Wanfang and China National Knowledge Infrastructure (CNKI) databases were retrivaled for the relationship between VDR gene variates and PCOS susceptibility published before 31th, May 2018. Crude odds ratios (ORs) and its 95% confidence intervals (95% CIs) in different comparisons were used to detected the strength of the association. All the statistical analyses of the present meta-analysis were performed by STATA version 12.0 software.

RESULTS

Totally, 3587 (PCOS group 1922; control group 1665) participants from 13 studies were included which met our inclusion criteria. A statistically significant association between VDR ApaI (rs7975232) polymorphism and PCOS susceptibility (C vs. A: OR = 1.19, 95%CI = 1.06~1.34, P = 0.004) was found in the overall population. After stratified by ethnicity, we showed that there is a significant association between VDR ApaI (rs7975232) polymorphism and susceptibility to PCOS in the Asian (C vs. A: OR = 1.21, 95%CI = 1.04~1.42, P = 0.016) population, but this association was not found in the Caucasian population. Additionally, a significant relationship between VDR BsmI (rs1544410) variates with PCOS susceptibility in the Asian (G vs. A: OR = 1.27, 95%CI = 1.06~1.53, P = 0.011) population, but this association was not found in the Caucasian population. We didn't find any association between VDR FokI (rs2228570), VDR TaqI (rs731236), VDR Tru9I (rs757343) and PCOS susceptibility in the overall and the subgroup populations.

CONCLUSIONS

Our findings demonstrated that VDR ApaI (rs7975232) and VDR BsmI (rs1544410) polymorphisms are correlated with susceptibility to PCOS in the Asian population and VDR TaqI (rs731236), VDR FokI (rs2228570), VDR Tru9I (rs757343) did not reveal a relationship with the PCOS susceptibility.

Association Between Vitamin D Receptor Gene Polymorphisms and Polycystic Ovary Syndrome Risk: A Meta-Analysis

Objective: Published studies have demonstrated a closer association between vitamin D receptor (VDR) gene polymorphisms and polycystic ovary syndrome (PCOS) risk, but the results were inconsistent. We therefore performed this meta-analysis to explore the precise associations between VDR gene polymorphisms and PCOS risk.

Methods: Five online electronic databases (PubMed, Embase, SCI index, CNKI and Wanfang) were searched. Odds ratios (ORs) with 95% confidence interval (CIs) were calculated to assess the association between VDR Fok I C/T (rs10735810), BsmI A/G (rs1544410), ApaI A/C (rs7975232), and TaqI T/C (rs731236) polymorphisms and PCOS risk. In addition, heterogeneity, accumulative/sensitivity analysis and publication bias were conducted to check the statistical power.

Results: Overall, 10 publications (31 independent case-control studies) involving 1,531 patients and 1,174 controls were identified. We found that the C mutation of ApaI A/C was a risk factor for PCOS (C vs. A: OR = 1.20, 95%CI = 1.06–1.35, P < 0.01, I² = 29.7%; CC vs. AA: OR = 1.49, 95%CI = 1.17–1.91, P < 0.01, I² = 0%; CC vs. AA+AC: OR = 1.36, 95%CI = 1.09–1.69, P = 0.01, I² = 12.8%). Moreover, the BsmI A/G polymorphism also showed a dangerous risk for PCOS in Asian population (G vs. A: OR = 1.62, 95%CI = 1.24–2.11, P < 0.01, I² = 0%; AG vs. AA: OR = 2.08, 95%CI = 1.26–3.20, P < 0.01, I² = 0%; GG vs. AA: OR = 2.21, 95%CI = 1.29–3.77, P < 0.01, I² = 0%; AG+GG vs. AA: OR = 2.12, 95%CI = 1.42–3.16, P < 0.01, I² = 0%). In addition, no significant association of Fok I C/T, and TaqI T/C polymorphisms was observed.

Conclusions: In summary, our meta-analysis suggested that VDR gene polymorphisms contribute to PCOS development, especially in Asian populations.

Polymorphic Variations in VDR Gene in Saudi Women with and Without Polycystic Ovary Syndrome (PCOS) and Significant Influence of Seven Polymorphic Sites on Anthropometric and Hormonal Parameters

BACKGROUND

This study was designed to evaluate the associations between vitamin D receptor (VDR) gene polymorphisms and biochemical characteristics of Saudi women with polycystic ovary syndrome (PCOS).

METHODS

Serum levels of LH, FSH, and Vitamin D were measured in 33 women: 16 patients and 17 normal controls (18 to 36 years). DNA was extracted and used for sequencing of the exons of VDR gene using ABI PRISM 3730xi Genetic Analyzer.

RESULTS

Weight, BMI, Vit D, LH and FSH levels were higher in the PCOS patients compared to control group, where Vit D level correlated positively and significantly with FSH, in the control, but showed a negative and non-significant correlation in the PCOS patients. Sequencing results showed extensive polymorphisms in both groups, but the differences in the frequencies were not significant. Demographic and hormonal parameters were compared in the different genotypes of the SNPs. Significant differences were ob served in the values of the studied parameters in rs11168276, rs11168266, rs3858733, rs121909790, rs11168265 and rs731236. Vitamin D level was influenced significantly by the genotypes of rs11168265 (AA) (p=0.008), rs11168276 (AA; p=0.018) and rs731236 (CC; p=0.024).

CONCLUSION

Vitamin D deficiency does not associate with PCOS in Saudi females. Several SNPs are identified in the VDR gene, in normal and PCOS females, but there is no difference in their frequencies between the two groups. The results show that polymorphism in VDR gene influences certain anthropometric and hormonal parameters in PCOS patients. Further detailed studies are required to confirm the associations between VDR and PCOS.

Apa-I polymorphism in VDR gene is related to metabolic syndrome in polycystic ovary syndrome: a cross-sectional study

BACKGROUND

Polycystic ovary syndrome (PCOS) is a common endocrine disorder determined by polygenic traits as well as environmental factors. Lower vitamin D levels have been detected in PCOS women and related to hormone and metabolic disturbances. Vitamin D acts in tissues through the vitamin D receptor (VDR). VDR gene variants have been associated with worse metabolic profile in the general population. We investigated the genotype and haplotype distribution of the Bsm-I (rs1544410), Apa-I (rs7975232), and Taq-I (rs731236) VDR gene polymorphisms in PCOS and non-hirsute women from southern Brazil. We further investigated the associations of these gene variants and their haplotypes with PCOS, vitamin D levels, and metabolic abnormalities, including the metabolic syndrome (MetS).

METHODS

A group of 191 women with PCOS (Rotterdam criteria) and 100 non-hirsute controls with regular ovulatory cycles were genotyped for all polymorphisms by real-time PCR, with allelic discrimination assays. MetS and the cutoffs for its isolated components were defined in accordance with the Joint Scientific Statement.

RESULTS

Women with PCOS were younger and had significantly higher BMI and total testosterone levels than controls (p < 0.05). The frequency of MetS in PCOS and controls was 26.5% and 4.8% respectively. The CC genotype of Apa-I entailed higher risk of MetS in PCOS (OR: 2.133; 95% CI 1.020-4.464, p = 0.042), and was associated with higher systolic blood pressure (p = 0.009), total cholesterol (p = 0.040), and LDL-cholesterol (p = 0.038) in both PCOS and control groups (two-way ANOVA). The frequencies of VDR haplotypes were similar in PCOS and control women.

CONCLUSIONS

The present results suggest that the Apa-I variant in VDR gene may be associated with MetS in southern Brazilian women with PCOS, and with blood pressure, total cholesterol, and LDL-c in women with and without PCOS.

Vitamin D Receptor TaqI Polymorphism Is Associated With Reduced Follicle Number in Women Utilizing Assisted Reproductive Technologies

PURPOSE

Calcitriol, or 1,25-hydroxycholecalciferol, is the active form of vitamin D. It binds and activates vitamin D receptor (VDR). Infertility and defective folliculogenesis have been observed in female vdr-knockout mice; however, whether VDR polymorphisms affect human ovarian responses to controlled ovarian stimulation (COS) remains unclear. We hypothesized that VDR polymorphisms are associated with infertility and COS responses. Thus, we evaluated the association between the TaqI, BsmI, and FokI VDR polymorphisms and ovarian responses in women undergoing COS.

METHODS

In this study, we recruited a control group (n = 121) comprising volunteers with a history of natural conception and a second group of women undergoing COS (n = 70). TaqI, BsmI, and FokI genotyping was performed via restriction fragment length polymorphism analysis or TaqMan qPCR and Sanger sequencing. Intrafollicular 25(OH)D contents were measured in follicular fluid collected from COS patients during oocyte retrieval. Ovarian response parameters were obtained from patient medical records.

RESULTS

There were no significant differences in the genotype frequencies of VDR polymorphisms (TaqI, BsmI and FokI) between the control and COS groups. However, the allele frequency of TaqI (C allele) was significantly lower in the COS group than in the control group (p = 0.02). Follicle number but not oocyte number was lower in patients with TaqI polymorphic (TC/CC) genotypes (p = 0.03). Importantly, the ratio between the number of follicles retrieved and intrafollicular estradiol concentrations was higher in patients with the TC/CC TaqI genotypes (p < 0.02).

CONCLUSION

We identified an association between the VDR TaqI polymorphism and reduced follicle number in women undergoing COS, suggesting that VDR signaling affects the ovarian response to stimulation via unknown mechanisms.