Yingying Qin

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.

NOBOX Homeobox Mutation Causes Premature Ovarian Failure

NOBOX (newborn ovary homeobox gene) is an oocyte-specific homeobox gene that plays a critical role in early folliculogenesis and represents a candidate gene for nonsyndromic ovarian failure. We investigated whether mutations in the NOBOX gene cause premature ovarian failure (POF). We sequenced the NOBOX gene in 96 white women with POF and discovered seven known single-nucleotide polymorphisms and four novel variations, two of which, p.Arg355His and p.Arg360Gln, cause missense mutations in the homeobox domain. Electrophoretic mobility shift assay (EMSA) confirmed that the missense mutation, p.Arg355His, disrupted NOBOX homeodomain binding to NOBOX DNA-binding element (NBE) and had a dominant negative effect on the binding of wild-type NOBOX to DNA. Our findings demonstrate that NOBOX mutations can cause POF.

Transcription Factor FIGLA is Mutated in Patients with Premature Ovarian Failure

Premature Ovarian Failure (POF) is a genetically heterogenous disorder that leads to hypergonadotropic ovarian failure and infertility. We screened 100 Chinese women with POF for mutations in the oocyte-specific gene FIGLA and identified three variants in four women: missense mutation c.11C --> A (p.A4E) was found in two women; deletion c. 15-36 del (p.G6fsX66), resulting in a frameshift that leads to haploinsufficiency, was found in one woman; and deletion c.419-421 delACA (p.140 delN) was found in one. Functional analyses by the yeast two-hybrid assay demonstrated that the p.140 delN mutation disrupted FIGLA binding to the TCF3 helix-loop-helix (HLH) domain. Our findings show that a subset of Chinese women with sporadic, premature ovarian failure harbor mutations in FIGLA.

Microarray Analyses of Newborn Mouse Ovaries Lacking Nobox

Abstract Nobox is a homeobox gene expressed in oocytes and critical in oogenesis. Nobox deficiency leads to rapid loss of postnatal oocytes. Early oocyte differentiation is poorly understood. We hypothesized that lack of Nobox perturbs global expression of genes preferentially expressed in oocytes as well as microRNAs. We compared Nobox knockout and wild-type ovaries using Affymetrix 430 2.0 microarray platform. We discovered that 28 (74%) of 38 of the genes downregulated more than 5-fold in the absence of Nobox were preferentially expressed in oocytes, whereas only 5 (15%) of 33 genes upregulated more than 5-fold in the absence of Nobox were preferentially expressed in oocytes. Protein-binding microarray helped identify nucleotide motifs that NOBOX binds and that several downregulated genes contain within putative promoter regions. MicroRNA population in newborn ovaries deficient of Nobox was largely unaffected. Genes whose proteins are predicted to be secreted but were previously unknown to be significantly expressed in early oogenesis were downregulated in Nobox knockouts and included astacin-like metalloendopeptidase (Astl), Jagged 1 (Jag1), oocyte-secreted protein 1 (Oosp1), fetuin beta (Fetub), and R-spondin 2 (Rspo2). In addition, pluripotency-associated genes Pou5f1 and Sall4 are drastically downregulated in Nobox-deficient ovaries, whereas testes-determining gene Dmrt1 is overexpressed. Our findings indicate that Nobox is likely an activator of oocyte-specific gene expression and suggest that the oocyte plays an important role in suppressing expression of male-determining genes, such as Dmrt1.

Fresh versus Frozen Embryos for Infertility in the Polycystic Ovary Syndrome

BACKGROUND The transfer of fresh embryos is generally preferred over the transfer of frozen embryos for in vitro fertilization (IVF), but some evidence suggests that frozen-embryo transfer may improve the live-birth rate and lower the rates of the ovarian hyperstimulation syndrome and pregnancy complications in women with the polycystic ovary syndrome. METHODS In this multicenter trial, we randomly assigned 1508 infertile women with the polycystic ovary syndrome who were undergoing their first IVF cycle to undergo either fresh-embryo transfer or embryo cryopreservation followed by frozen-embryo transfer. After 3 days of embryo development, women underwent the transfer of up to two fresh or frozen embryos. The primary outcome was a live birth after the first embryo transfer. RESULTS Frozen-embryo transfer resulted in a higher frequency of live birth after the first transfer than did fresh-embryo transfer (49.3% vs. 42.0%), for a rate ratio of 1.17 (95% confidence interval [CI], 1.05 to 1.31; P=0.004). Women who underwent frozen-embryo transfer also had a lower frequency of pregnancy loss (22.0% vs. 32.7%), for a rate ratio of 0.67 (95% CI, 0.54 to 0.83; P<0.001), and of the ovarian hyperstimulation syndrome (1.3% vs. 7.1%), for a rate ratio of 0.19 (95% CI, 0.10 to 0.37; P<0.001), but a higher frequency of preeclampsia (4.4% vs. 1.4%), for a rate ratio of 3.12 (95% CI, 1.26 to 7.73; P=0.009). There were no significant between-group differences in rates of other pregnancy and neonatal complications. There were five neonatal deaths in the frozen-embryo group and none in the fresh-embryo group (P=0.06). CONCLUSIONS Among infertile women with the polycystic ovary syndrome, frozen-embryo transfer was associated with a higher rate of live birth, a lower risk of the ovarian hyperstimulation syndrome, and a higher risk of preeclampsia after the first transfer than was fresh-embryo transfer. (Funded by the National Basic Research Program of China and others; ClinicalTrials.gov number, NCT01841528.).

Genetics of primary ovarian insufficiency: new developments and opportunities

BACKGROUND Primary ovarian insufficiency (POI) is characterized by marked heterogeneity, but with a significant genetic contribution. Identifying exact causative genes has been challenging, with many discoveries not replicated. It is timely to take stock of the field, outlining the progress made, framing the controversies and anticipating future directions in elucidating the genetics of POI. METHODS A search for original articles published up to May 2015 was performed using PubMed and Google Scholar, identifying studies on the genetic etiology of POI. Studies were included if chromosomal analysis, candidate gene screening and a genome-wide study were conducted. Articles identified were restricted to English language full-text papers. RESULTS Chromosomal abnormalities have long been recognized as a frequent cause of POI, with a currently estimated prevalence of 10–13%. Using the traditional karyotype methodology, monosomy X, mosaicism, X chromosome deletions and rearrangements, X-autosome translocations, and isochromosomes have been detected. Based on candidate gene studies, single gene perturbations unequivocally having a deleterious effect in at least one population include Bone morphogenetic protein 15 (BMP15), Progesterone receptor membrane component 1 (PGRMC1), and Fragile X mental retardation 1 (FMR1) premutation on the X chromosome; Growth differentiation factor 9 (GDF9), Folliculogenesis specific bHLH transcription factor (FIGLA), Newborn ovary homeobox gene (NOBOX), Nuclear receptor subfamily 5, group A, member 1 (NR5A1) and Nanos homolog 3 (NANOS3) seem likely as well, but mostly being found in no more than 1–2% of a single population studied. Whole genome approaches have utilized genome-wide association studies (GWAS) to reveal loci not predicted on the basis of a candidate gene, but it remains difficult to locate causative genes and susceptible loci were not always replicated. Cytogenomic methods (array CGH) have identified other regions of interest but studies have not shown consistent results, the resolution of arrays has varied and replication is uncommon. Whole-exome sequencing in non-syndromic POI kindreds has only recently begun, revealing mutations in the Stromal antigen 3 (STAG3), Synaptonemal complex central element 1 (SYCE1), minichromosome maintenance complex component 8 and 9 (MCM8, MCM9) and ATP-dependent DNA helicase homolog (HFM1) genes. Given the slow progress in candidate-gene analysis and relatively small sample sizes available for GWAS, family-based whole exome and whole genome sequencing appear to be the most promising approaches for detecting potential genes responsible for POI. CONCLUSION Taken together, the cytogenetic, cytogenomic (array CGH) and exome sequencing approaches have revealed a genetic causation in ∼20–25% of POI cases. Uncovering the remainder of the causative genes will be facilitated not only by whole genome approaches involving larger cohorts in multiple populations but also incorporating environmental exposures and exploring signaling pathways in intragenic and intergenic regions that point to perturbations in regulatory genes and networks.

Mutation analysis of NOBOX homeodomain in Chinese women with premature ovarian failure.

The newborn ovary homeobox gene (NOBOX) is an oocyte-specific homeobox gene that plays a critical role in early folliculogenesis, thus representing an attractive candidate gene for nonsyndromic ovarian failure. We investigated whether perturbation in the homeodomain region of NOBOX was present in Chinese women with premature ovarian failure (POF). We sequenced 200 Chinese patients with POF, and discovered only two known single nucleotide polymorphisms: in intron 6 (c.1154+11 T>C and c.1155-22 G>A); neither offers plausible explanations for POF. Failing to find causative mutation contrasts with our previous study in a caucasian sample, in which we found plausible homeobox mutation in 1 of 96 POF cases. Mutations in the homeobox domain of NOBOX are not common explanations for POF in Chinese women.

Association of basal serum testosterone levels with ovarian response and in vitro fertilization outcome

BackgroundTo evaluate basal testosterone (T) levels during follicular phase of the menstrual cycle as a predictor for ovarian response and in vitro fertilization (IVF) outcome.MethodWe analyzed data retrospectively from hospital-based IVF center including one thousand two hundred and sixty Chinese Han women under their first IVF cycle reached the ovum pick-up stage, without polycystic ovary syndrome (PCOS) or endometriosis undergoing long IVF protocol. Patients were divided into 2 groups. Group 1: patients with diminished ovarian reserve (basal FSH >10 IU/L) (n = 187); Group 2: patients with normal ovarian reserve (basal FSH < = 10 IU/L) (n = 1073). We studied the association of basal T levels with ovarian response and IVF outcome in the two groups. Long luteal down-regulation protocol was used in all patients, that is, the gonadotropin releasing hormone agonist was administered in the midluteal phase of the previous cycle and use of recombinant FSH was started when satisfactory pituitary desensitization was achieved.ResultsBasal T levels were markly different between pregnant and non-pregnant women in Group 1; whereas not in Group 2. A testosterone level of 47.85 ng/dl was shown to predict pregnancy outcome with a sensitivity of 52.8% and specificity of 65.3%; and the basal T was correlated with the numbers of large follicles (> 14 mm) on HCG day in Group 1. Significantly negative correlations were observed between basal T, days of stimulation and total dose of gonadotropins after adjusting for confounding factors in both groups.ConclusionIn women with diminished ovarian reserve, basal T level was a predictor for the number of large follicles on HCG day and pregnancy outcome; but could not in those with normal serum FSH. Basal T levels were associated with both days of stimulation and total dose of gonadotropins, indicating that lower level of T might relate with potential ovarian poor response.

Adaptive fuzzy control system of a servomechanism for electro-discharge machining combined with ultrasonic vibration

Abstract For electro-discharge machining (EDM), only when in the optimum state can the highest material removal rate be realized. In the practical machining process, the timely elevation of the tool electrode, which ordinarily occupies quite a lot of time, is needed to eliminate chipping. In this paper, an adaptive fuzzy control system of a servomechanism for EDM combined with ultrasonic vibration is studied. This control system can adjust the discharge pulse parameters in a timely manner, and also the gap between the tool electrode and the workpiece material, therefore, the machining state can be optimal, by which the EDM combined with ultrasonic vibration is improved and the machining efficiency is increased. In addition, a stimulation program is designed by means of Microsoft Visual Basic software.

ESR1, HK3 and BRSK1 gene variants are associated with both age at natural menopause and premature ovarian failure

BackgroundPremature ovarian failure (POF) is a complex and heterogeneous disorder that is influenced by multiple genetic components. Numerous candidate gene studies designed to identify POF susceptibility loci have been published, but most positive findings have not been confirmed in follow up studies. We sought to determine if sequence variants previously associated with age at natural menopause (AANM) or early menopause (EM) contribute as well to genetic susceptibility to POF.MethodsOur study was performed on 371 unrelated idiopathic women with POF and 800 women controls, all Chinese Han. Thirty six SNPs from previous genome-wide association studies (GWAS) responsible for AANM or EM and 3 additional SNPs in ESR1, and 2 additional SNPs in PTHB1 were tested using the Sequenom MassARRAY iPLEX platform for genotyping.ResultsThree SNPs - rs2278493 in HK3, rs2234693 in ESR1 and rs12611091 in BRSK1 - showed nominally significant association with POF. Thus, a plausible relationship could exist between ESR1, BRSK1, HK3 and POF.ConclusionsThis largest association study undertaken to determine correlation between POF and AANM/EM revealed three significant SNPs (rs2278493, rs2234693, and rs12611091). All are associated with not only AAWM and EM but also POF. Insights into shared genetic susceptibility between POF and AANM/EM will provide novel entry points for unraveling genetic mechanism involved in ovarian reserve and oocyte aging processes.