Yuehong Bian

Genome-wide association study identifies susceptibility loci for polycystic ovary syndrome on chromosome 2p16.3, 2p21 and 9q33.3

Polycystic ovary syndrome (PCOS) is a common metabolic disorder in women. To identify causative genes, we conducted a genome-wide association study (GWAS) of PCOS in Han Chinese. The discovery set included 744 PCOS cases and 895 controls; subsequent replications involved two independent cohorts (2,840 PCOS cases and 5,012 controls from northern Han Chinese; 498 cases and 780 controls from southern and central Han Chinese). We identified strong evidence of associations between PCOS and three loci: 2p16.3 (rs13405728; combined P-value by meta-analysis Pmeta = 7.55 × 10−21, odds ratio (OR) 0.71); 2p21 (rs13429458, Pmeta = 1.73 × 10−23, OR 0.67); and 9q33.3 (rs2479106, Pmeta = 8.12 × 10−19, OR 1.34). These findings provide new insight into the pathogenesis of PCOS. Follow-up studies of the candidate genes in these regions are recommended.

Hypomethylation of the LH/Choriogonadotropin Receptor Promoter Region Is a Potential Mechanism Underlying Susceptibility to Polycystic Ovary Syndrome

Our previous genome-wide association study identified LH/choriogonadotropin receptor (LHCGR) as a susceptibility gene for polycystic ovary syndrome (PCOS). The objective of this study was to determine whether the genetic or epigenetic components associated with LHCGR participate in the pathogenesis of PCOS. The exons and flanking regions of LHCGR were sequenced from 192 women with PCOS, and no novel somatic mutations were identified. In addition, the methylation statuses of 6 cytosine-phosphate-guanine (CpG) sites in the promoter region of LHCGR were measured by pyrosequencing using peripheral blood cells from 85 women with PCOS and 88 control women. We identified 2 hypomethylated sites, CpG -174 (corrected P = .018) and -111 (corrected P = .006). Bisulfite sequencing then was performed to replicate these findings and detect additional CpG sites in the promoter. CpG +17 was significantly hypomethylated in women with PCOS (corrected P = .02). Methylation statuses were further evaluated using granulosa cells (GCs), and the region described was hypomethylated as a whole (P = .004) with 8 significantly hypomethylated sites (CpG -174, -148, -61, -43, -8, +10, +17, and +20). Transcription of LHCGR was elevated in women with PCOS compared with that in control women (P < .01). These findings were consistent with the decreased LHCGR methylation status associated with PCOS. The tendency of LHCGR to be hypomethylated across different tissues and its corresponding expression level suggest that hypomethylation of LHCGR is a potential mechanism underlying susceptibility to PCOS. Further studies are needed to evaluate whether a causal relationship exists between LHCGR methylation status and PCOS.

Family association study between INSR gene polymorphisms and PCOS in Han Chinese

BackgroundPolycystic ovary syndrome (PCOS) is a complex disease having both genetic and environmental components. Candidate genes with insulin metabolism have been hypothesized to be involved in the etiology of this syndrome. In the present study, we investigated the genetic association between polymorphisms in the insulin receptor (INSR) gene and PCOS.MethodsA total of 260 family trios were recruited and performed a family-based analysis to assess linkage and association between four single nucleotide polymorphisms (SNPs) (rs1799817, rs2059807, rs8108622 and rs10500204) of INSR gene and PCOS.ResultsUsing the transmission disequilibrium test (TDT), we failed to find that rs1799817 (p = 0.486), rs2059807 (p = 0.195), rs8108622 (p = 0.866) and rs10500204 (p = 1.0) were significantly overtransmitted to PCOS offspring from their parents.ConclusionNo significant evidence of association or linkage was found in the four tested markers, indicating that our family samples did not support susceptibility of the INSR gene to PCOS.

Common Variant rs9939609 in Gene FTO Confers Risk to Polycystic Ovary Syndrome

Background Fat mass and obesity-associated gene (FTO) has been associated with obesity, especially the common variant rs9939609. Polycystic ovary syndrome (PCOS) is a complex endocrine-metabolic disorder and over 50% of patients are overweight/obese. Thus FTO is a potential candidate gene for PCOS but their relationship is confusing and remains to be clarified in different population with a large sample size. Method This study was performed adopting a two-stage design by genotyping SNP rs9939609. The first set comprise of 741 PCOS and 704 control subjects, with data from our previous GWAS. The second phase of replication study was performed among another independent group of 2858 PCOS and 2358 control subjects using TaqMan-MGB probe assay. All subjects are from Han Chinese. Results The less meaningful association of FTO rs9939609 and PCOS discovered in GWAS (P = 2.47E-03), was further confirmed in the replication study (P = 1.86E-09). Using meta-analysis, the P-meta value has reached 6.89E-12, over-exceeding the genome-wide association level of 5.00E-8. By combination, the P value was 1.26E-11 and after BMI adjustment it remained significant(P = 1.82E-06). To further elucidate whether this association is resulted from obesity or PCOS per se, the samples were divided into two groups–obese and non-obese PCOS, and the results were still positive in obese group (P obese = 5.81E-05, OR = 1.55), as well as in non-obese PCOS group (P non-obese = 7.06E-04, OR = 1.28). Conclusion Variant rs9939609 in FTO is associated with PCOS in Chinese women, not only in obese PCOS subjects, but also in non-obese cases.

Polycystic ovary syndrome susceptibility single nucleotide polymorphisms in women with a single PCOS clinical feature

STUDY QUESTION What is the direct genetic contribution of the polycystic ovary syndrome (PCOS) susceptibility single nucleotide polymorphisms (SNPs), identified by previous genome-wide association studies (GWAS) to the definitive clinical features of the syndrome? SUMMARY ANSWER Each single PCOS clinical feature had a specific genetic association, and rs4385527 in the chromosome 9 open reading frame 3 (C9orf3) conferred a particular risk to the three defined PCOS clinical features in this study, which suggested its fundamental role in the etiology of PCOS. WHAT IS KNOWN ALREADY PCOS is a heterogeneous disorder characterized by anovulation (OA), hyperandrogenism (HA) and polycystic ovary morphology (PCOM). Two previous GWAS in China have identified 15 independent susceptibility SNPs related to PCOS (PCOS-SNPs). However, little is known about the candidate gene of each clinical feature. STUDY DESIGN, SIZE, DURATION Case-control study. Three independent groups of women were recruited from 2010 to 2012: 746 subjects with OA only, 278 subjects with HA only and 536 subjects with PCOM only. A total of 1790 healthy women with none of the above pathological characteristics were also enrolled as control subjects during the same time period. PARTICIPANTS/MATERIALS, SETTING, METHODS All participants were women of reproductive age. Genotype and allelic frequencies of 15 PCOS-SNPs were determined in all subjects using direct sequencing and Sequenom Arrays. The allelic frequencies of each case group were compared with the controls. MAIN RESULTS AND THE ROLE OF CHANCE After adjustment for age and BMI, variants in luteinizing hormone/choriogonadotropin receptor (LHCGR) (rs13405728), C9orf3 (rs4385527) and insulin receptor gene (INSR) (rs2059807) were strongly associated with OA (Padjust < 0.01, <0.001 and <0.05, respectively); rs4385527 in C9orf3 was strongly associated with HA (Padjust< 0.001); variants in the thyroid adenoma associated gene (THADA) (rs13429458 and rs12478601), DENN/MADD domain containing 1A (DENND1A)(rs10818854), and C9orf3 (rs4385527) were significantly associated with PCOM (Padjust < 0.01, <0.001, <0.05 and <0.001, respectively). LIMITATIONS, REASONS FOR CAUTION The sample size of some case groups was relatively small, which therefore limited the statistical power of the analysis to a certain extent. WIDER IMPLICATIONS OF THE FINDINGS The present study indicates a potential common genetic basis of three PCOS clinical features. Other specific associated genes may play a synergistic role, leading to heterogeneous pathophysiological changes. Additionally, the increased frequency of PCOS-risk alleles in women with single PCOS clinical features suggests that these subjects have an elevated risk of developing the syndrome, although they cannot be currently diagnosed. STUDY FUNDING/COMPETING INTERESTS This research was supported by the National Basic Research Program of China (973 Program) (2012CB944700, 2011CB944502), the National Key Technology Research and Development Program(2011BAI17B00), the National Natural Science Foundation of China (81430029, 81201441, 81490743, 31371453), the Scientific Research Foundation of Shandong Province of Outstanding Young Scientist (2012BSE27089) and the Fundamental Research Funds of Shandong University(2014GN025). There were no competing interests.

Association of Vascular Endothelial Growth Factor Gene Polymorphisms with Recurrent Spontaneous Abortion in Chinese Han Women

Citation Xing X, Yan J, Zhao Y, You L, Bian Y, Chen Z‐J. Association of vascular endothelial growth factor gene polymorphisms with recurrent spontaneous abortion in Chinese Han women. Am J Reprod Immunol 2011; 65: 521–525

LHX1 mutation screening in 96 patients with müllerian duct abnormalities

OBJECTIVE To investigate whether LHX1 gene mutations exist in Han Chinese patients with müllerian duct abnormalities (MDAs). DESIGN Mutation screening. SETTING University hospital. PATIENT(S) Ninety-six MDA patients and 105 control subjects from a Han Chinese population. The parents of the patients carrying the genetic variation were also screened. INTERVENTION(S) Gene sequencing. MAIN OUTCOME MEASURE(S) Karyotype, LHX1 gene sequencing. RESULT(S) We found no significant mutation in coding regions of LHX1. However, there is a new rare polymorphism of LHX1 gene, c.1070-1081del, found in 1 out of 77 incomplete müllerian fusion patients and 1 out of 105 control individuals in the Han Chinese population (thus affecting ∼1% of Han Chinese). CONCLUSION(S) No causative perturbation was identified in the LHX1 gene. Mutations in the coding regions of LHX1 may not be a common genetic etiologic factor involved in Han Chinese MDA patients.

FADS1-FADS2 gene cluster confers risk to polycystic ovary syndrome.

Dyslipidemia is common in polycystic ovary syndrome (PCOS). This study was aimed to investigate whether fatty acid desaturase genes (FADS), a dyslipidemia-related gene cluster, are associated with PCOS. We scanned variations of FADS genes using our previous data of genome-wide association study (GWAS) for PCOS and selected rs174570 for further study. The case-control study was conducted in an independent cohort of 1918 PCOS cases and 1889 age-matched controls and family-based study was conducted in a set of 243 core family trios with PCOS probands. Minor allele frequency (allele T) of rs174570 was significantly lower in PCOS cases than that in age-matched controls (P = 2.17E-03, OR = 0.85), even after adjustment of BMI and age. PCOS subjects carrying CC genotype had higher testosterone level and similar lipid/glucose level compared with those carrying TT or TC genotype. In trios, transmission disequilibrium test (TDT) analysis revealed risk allele C of rs174570 was significantly over-transmitted (P = 2.00E-04). Decreased expression of FADS2 was detected in PCOS cases and expression quantitative trait loci (eQTL) analysis revealed the risk allele C dosage was correlated with the decline of FADS2 expression (P = 0.002). Our results demonstrate that FADS1-FADS2 are susceptibility genes for PCOS.

Mutational analysis of IZUMO1R in women with fertilization failure and polyspermy after in vitro fertilization

PurposeThe etiology of fertilization failure and polyspermy during assisted reproductive technology (ART) remains elusive. The aim of this study was to determine whether mutations in the IZUMO1 receptor (IZUMO1R) gene, which is essential for mammalian fertilization, contribute to the pathogenesis of fertilization failure or polyspermy in humans.MethodsWe recruited 215 female subjects with fertilization failure/poor fertilization, 330 females with polyspermy, and 300 matched controls. All subjects underwent IVF treatment. Peripheral blood DNA of cases was extracted and screened for mutations in IZUMO1R gene.ResultsFour rare single nucleotide polymorphisms (SNPs) of the IZUMO1R were identified among specimens from patients with fertilization failure and polyspermy but were absent in the 300 control subjects. These included a missense SNP (rs76779571 in exon 4), which was found in two fertilization failure patients, and a nonsynonymous SNP (rs61742524 in exon 1) and two synonymous SNPs (rs76781645 in exon 1 and rs377369966 in intron 2), which were found among three polyspermy cases.ConclusionsThe variations in IZUMO1R might play a role in the pathogenesis of fertilization failure and polyspermy, and the putative functions and effects of these rare variants require further studies.