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STUDY QUESTION Is there any methylome alteration in women with PCOS who were diagnosed using the new international evidence-based guidelines? SUMMARY ANSWER A total of 264 differentially methylated probes (DMPs) and 53 differentially methylated regions (DMRs) were identified in patients with PCOS and healthy controls. WHAT IS KNOWN ALREADY PCOS is a common endocrine disorder among women of reproductive age and polycystic ovarian morphology (PCOM) is one of the main features of the disease. Owing to the availability of more sensitive ultrasound machines, the traditional diagnosis of PCOM according to the Rotterdam criteria (≥12 antral follicles per ovary) is currently debated as there is a risk of overdiagnosis. The new international evidence-based guidelines set the threshold for PCOM as ≥20 antral follicles per ovary when using endovaginal ultrasound transducers with a frequency bandwidth that includes 8 MHz. However, current DNA methylation studies in PCOS are still based on the Rotterdam criteria. This study aimed to explore aberrant DNA methylation in patients diagnosed with PCOS according to the new evidence-based guidelines. STUDY DESIGN, SIZE, DURATION This cross-sectional case–control study included 34 PCOS cases diagnosed using new international evidence-based guidelines and 36 controls. PARTICIPANTS/MATERIALS, SETTING, METHODS A total of 70 women, including 34 PCOS cases and 36 controls, were recruited. DNA extracted from whole blood samples of participants were profiled using array technology. Data quality control, preprocessing, annotation, and statistical analyses were performed. Least absolute shrinkage and selection operator (LASSO) regression were used to build a PCOS diagnosis model with DNA methylation sites. MAIN RESULTS AND THE ROLE OF CHANCE We identified 264 DMPs between PCOS cases and controls, which were mainly located in intergenic regions or gene bodies of the genome, CpG open sea sites, and heterochromatin of functional elements. Pathway enrichment analysis showed that DMPs were significantly enriched in biological processes involved in triglyceride regulation. Three of these DMPs overlapped with the PCOS susceptibility genes thyroid adenoma-associated protein (THADA), aminopeptidase O (AOPEP), and tripartite motif family-like protein 2 (TRIML2). Fifty-three DMRs were identified and their annotated genes were largely enriched in allograft rejection, thyroid hormone production, and peripheral downstream signaling effects. Two DMRs were closely related to the PCOS susceptibility genes, potassium voltage-gated channel subfamily A member 4 (KCNA4) and farnesyl-diphosphate farnesyltransferase 1 (FDFT1). Finally, based on LASSO regression, we built a methylation marker model with high accuracy for PCOS diagnosis (AUC=0.952). LIMITATIONS, REASONS FOR CAUTION The study cohort was single-center and the sample size was relatively limited. Further analyses with a larger number of participants are required. WIDER IMPLICATIONS OF THE FINDINGS This is the first study to identify DNA methylation alterations in women with PCOS diagnosed using the new international evidence-based guideline, and it provided new molecular insight into the application of the new guidelines. STUDY FUNDING/COMPETING INTEREST(S) This study was supported by the National Key Research and Development Program of China (2021YFC2700400), Basic Science Center Program of NSFC (31988101), CAMS Innovation Fund for Medical Sciences (2021-I2M-5-001), National Natural Science Foundation of China (32370916, 82071606, 82101707, 82192874, and 31871509), Shandong Provincial Key Research and Development Program (2020ZLYS02), Taishan Scholars Program of Shandong Province (ts20190988), and Fundamental Research Funds of Shandong University. The authors declare no conflicts of interest. TRIAL REGISTRATION NUMBER N/A. [ABSTRACT FROM AUTHOR]

STUDY QUESTION Was polycystic ovary syndrome (PCOS), which impairs fertility and adheres to the evolutionary paradox, subject to evolutionary selection during ancestral times and did rapidly diminish in prevalence? SUMMARY ANSWER This study strengthened the hypothesis that positive selection of genetic variants occurred and may account for the high prevalence of PCOS observed today. WHAT IS KNOWN ALREADY PCOS is a complex endocrine disorder characterized by both reproductive and metabolic disturbances. As a heritable disease that impairs fertility, PCOS should diminish rapidly in prevalence; however, it is the most common cause of female subfertility globally. Few scientific genetic studies have attempted to provide evidence for the positive selection of gene variants underlying PCOS. STUDY DESIGN, SIZE, DURATION We performed an evolutionary analysis of 2,504 individuals from 14 populations of the 1000 Genomes Project. PARTICIPANTS/MATERIALS, SETTING, METHODS We tested the signature of positive selection for 37 single-nucleotide polymorphisms (SNPs) associated with PCOS in previous genome-wide association studies using six parameters of positive selection. MAIN RESULTS AND THE ROLE OF CHANCE Analyzing the evolutionary indices together, there was obvious positive selection at the PCOS-related SNPs loci, especially within the original evolution window of humans, demonstrated by significant Tajima's D values. Compared to the genome background, six of the 37 SNPs in or close to five genes (DENN domain-containing protein 1A: DENND1A , chromosome 9 open reading frame 3: AOPEP , aminopeptidase O: THADA , diacylglycerol kinase iota: DGKI , and netrin receptor UNC5C: UNC5C) showed significant evidence of positive selection, among which DENND1A , AOPEP , and THADA represent the set of most established susceptibility genes for PCOS. LIMITATIONS, REASONS FOR CAUTION First, only well-documented SNPs were selected from well-designed experiments. Second, it is difficult to determine which hypothesis of PCOS evolution is at play. After considering the most significant functions of these genes, we found that they had a wide variety of functions with no obvious association between them. WIDER IMPLICATIONS OF THE FINDINGS Our findings provide additional evidence for the positive evolution of PCOS. Our analyses require confirmation in a larger study with more evolutionary indicators and larger data range. Further research to identify the roles of the DENND1A , AOPEP , THADA , DGKI , and UNC5C genes is also necessary. STUDY FUNDING/COMPETING INTEREST(S) This study was supported by the National Key Research and Development Program of China (2021YFC2700400 and 2021YFC2700701), Basic Science Center Program of NSFC (31988101), CAMS Innovation Fund for Medical Sciences (2021-I2M-5-001), National Natural Science Foundation of China (82192874, 31871509, and 82071606), Shandong Provincial Key Research and Development Program (2020ZLYS02), Taishan Scholars Program of Shandong Province (ts20190988), and Fundamental Research Funds of Shandong University. The authors have no conflicts of interest to disclose. TRIAL REGISTRATION NUMBER N/A. [ABSTRACT FROM AUTHOR]

Study Question: What are the genetic causes of oocyte maturation defects?Summary Answer: A homozygous splicing variant (c.788 + 3A>G) in TATA-box binding protein like 2 (TBPL2) was identified as a contributory genetic factor in oocyte maturation defects.What Is Known Already: TBPL2, a vertebrate oocyte-specific general transcription factor, is essential for oocyte development. TBPL2 variants have not been studied in human oocyte maturation defects.Study Design, Size, Duration: Two infertile families characterized by oocyte maturation defects were recruited for whole-exome sequencing (WES).Participants/materials, Setting, Methods: Genomic DNA was extracted from peripheral blood for WES analysis. Sanger sequencing was performed for data validation. Pathogenicity of variants was predicted by in silico analysis. Minigene assay and single-oocyte RNA sequencing were performed to investigate the effects of the variant on mRNA integrity and oocyte transcriptome, respectively.Main Results and the Role Of Chance: A homozygous splicing variant (c.788 + 3A>G) in TBPL2 was identified in two unrelated families characterized by oocyte maturation defects. Haplotype analysis indicated that the disease allele of Families 1 and 2 was independent. The variant disrupted the integrity of TBPL2 mRNA. Transcriptome sequencing of affected oocytes showed that vital genes for oocyte maturation and fertilization were widely and markedly downregulated, suggesting that a mutation in the transcriptional factor, TBPL2, led to global gene alterations in oocytes.Limitations, Reasons For Caution: Limitations include the lack of direct functional evidence. Owing to the scarcity of human oocyte samples, only two immature MI oocytes were obtained from the patients, and we could only investigate the effect of the mutation at the transcriptional level by high-throughput sequencing technology. No extra oocytes were obtained to assess the transcriptional activity of the mutant oocytes by immunofluorescence, or investigate the effects on the binding of TBPL2 caused by the mutation.Wider Implications Of the Findings: Our findings highlight a critical role of TBPL2 in female reproduction and identify a homozygous splicing mutation in TBPL2 that might be related to defects in human oocyte maturation. This information will facilitate the genetic diagnosis of infertile individuals with repeated failures of IVF, providing a basis for genetic counseling.Study Funding/competing Interest(s): This study was supported by the National Key Research and Development Program of China (2018YFC1004000, 2017YFC1001504 and 2017YFC1001600), the National Natural Science Foundation of China (81871168, 31900409 and 31871509), the Foundation for Distinguished Young Scholars of Shandong Province (JQ201816), the Innovative Research Team of High-Level Local Universities in Shanghai (SSMU-ZLCX20180401) and the Fundamental Research Funds of Shandong University. The authors have no competing interests to declare.Trial Registration Number: N/A. [ABSTRACT FROM AUTHOR]

Study Question: Does the inheritance of polycystic ovary syndrome (PCOS) susceptibility single-nucleotide polymorphism affect the phenotype of offspring?Summary Answer: Male offspring who inherit PCOS-related genetic variations from PCOS mothers were more susceptible to developing the metabolic abnormality in their later life.What Is Known Already: Genetic factors are considered the major etiology of PCOS. Previous studies have highlighted that offspring of women with PCOS had an increased risk of the same disease or PCOS-like symptoms.Study Design, Size, Duration: The study involved 172 children born to women with PCOS and 529 children born to non-PCOS women. All offspring were conceived by assisted reproductive technologies.Participants/materials, Setting, Methods: The offspring ranged from 1 to 8 years old. Metabolic phenotype analyses were performed in offspring aged from 2 to 8 (N = 619). Sanger sequencing, TaqMan and Sequenom MassARRAY were used to sequence the samples.Main Results and the Role Of Chance: In male offspring, the fasting insulin (FINS) (P = 0.037) homeostasis model assessment of insulin resistance (HOMA-IR) (P = 0.038) and the homeostasis model assessment of pancreatic beta-cell function (HOMA-β) (P = 0.038) levels were higher in offspring of PCOS mothers compared to controls. In female offspring, PCOS offspring had a significantly higher anti-Müllerian hormone levels (P = 0.001) compared to those from control mothers. In male offspring of PCOS mothers, subjects with a T allele at rs2349415 in the gene FSHR had higher FINS (P = 0.023), HOMA-IR (P = 0.030) and HOMA-β levels (P = 0.013) than those in the homozygous CC group. The same increased trend in FINS, HOMA-IR and HOMA-β levels could be found in the CC and TC group in rs2268361 located in gene FSHR compared to the TT group (P = 0.029, P = 0.030, P = 0.046, respectively). As for rs10818854 in the DENND1A gene, the AA and AG group had a higher FINS (P = 0.037) and HOMA-β (P = 0.008) levels than the homozygous CC group.Limitations, Reasons For Caution: Firstly, the offspring may be too young to see any phenotype changes. Secondly, this study only analyzed the differences of genotype frequency using the dominant model instead of all three models due to the limited sample size of the homozygous model. The results, therefore, should be replicated and performed in a larger sample size population. Thirdly, environmental impacts cannot be ruled out.Wider Implications Of the Findings: The findings presented in this thesis add to our understanding the changes in offspring born to PCOS women and remind us to consider early intervention to avoid more severe effects.Study Funding/competing Interest(s): This study was supported by the National Key Research and Development Program of China 2017YFC1001000 (to Z.-J.C.), the National Natural Science Foundation of China 81430029 (to Z.-J.C.), 81622021 and 31571548 (to H.Z.), the National Natural Science Foundation of Shandong Province JQ201816 (to H.Z.) and Shandong Provincial Key Research and Development Program 2017G006036 (to L.-L.C.) and 2018YFJH0504 (to Z.-J.C.). There are no conflicts of interest to declare.Trial Registration Number: N/A. [ABSTRACT FROM AUTHOR]