No evidence of the inactivating mutation (C566T) in the follicle-stimulating hormone receptor gene in Brazilian women with premature ovarian failure

RANKL is a new Epigenetic Biomarker for the Vasomotor Symptom During Menopause

During menopausal transition, decreased level of estrogen brings a number of physiological problems and hormonal changes. In this study, promoter methylation of RANKL and FSHR genes were identified in 30 premenopausal and 35 postmenopausal women using methylation-specific high resolution melting (MS-HRM) analysis. The statistical analyses and their association with patient characteristics were performed by Pearson χ² and Fisher's exact test (p <0.05). The methylated RANKL gene was detected in 16 postmenopausal cases, and 12 (75.0%) of the RANKL methylated cases had hot flashes (p = 0.024). The methylated FSHR gene was detected in 18 postmenopausal cases, and 13 (75.0%) of the methylated cases had hot flashes (p = 0.028). In vitro studies demonstrated the association between RANKL expression, FSH level and hot flashes in the mouse. Although lack of epigenetic studies in this field proves our results crucial and therefore, our results showed magnitude of epigenetic profiles of Turkish Cypriot post-menopausal women. This was the first study which has investigated the RANKL and FSHR methylation and their relationship with hot flashes in postmenopausal women.

The Genetics of Non-Syndromic Primary Ovarian Insufficiency: A Systematic Review

Several causes for primary ovarian insufficiency (POI) have been described, including iatrogenic and environmental factor, viral infections, chronic disease as well as genetic alterations. The aim of this review was to collect all the ge- netic mutations associated with non-syndromic POI. All studies, including gene screening, genome-wide study and as- sessing genetic mutations associated with POI, were included and analyzed in this systematic review. Syndromic POI and chromosomal abnormalities were not evaluated. Single gene perturbations, including genes on the X chromosome (such as BMP15, PGRMC1 and FMR1) and genes on autosomal chromosomes (such as GDF9, FIGLA, NOBOX, ESR1, FSHR and NANOS3) have a positive correlation with non-syndromic POI. Future strategies include linkage analysis of families with multiple affected members, array comparative genomic hybridization (CGH) for analysis of copy number variations, next generation sequencing technology and genome-wide data analysis. This review showed variability of the genetic factors associated with POI. These findings may help future genetic screening studies on large cohort of women.

Genetics of the ovarian reserve

Primordial follicles or non-growing follicles (NGFs) are the functional unit of reproduction, each comprising a single germ cell surrounded by supporting somatic cells. NGFs constitute the ovarian reserve (OR), prerequisite for germ cell ovulation and the continuation of the species. The dynamics of the reserve is determined by the number of NGFs formed and their complex subsequent fates. During the reproductive lifespan, the OR progressively diminishes due to follicle atresia as well as recruitment, maturation, and ovulation. The depletion of the OR is the major determining driver of menopause, which ensues when the number of primordial follicles falls below a threshold of ∼1,000. Therefore, genes and processes involved in follicle dynamics are particularly important to understand the process of menopause, both in the typical reproductive lifespan and in conditions like primary ovarian insufficiency, defined as menopause before age 40. Genes and their variants that affect the timing of menopause thereby provide candidates for diagnosis of and intervention in problems of reproductive lifespan. We review the current knowledge of processes and genes involved in the development of the OR and in the dynamics of ovarian follicles.

Impact of follicle-stimulating hormone receptor variants in female infertility

PURPOSE

Follicle-stimulating hormone (FSH) and its receptor play a major role in the development of follicles and regulation of steroidogenesis in the ovary and spermatogenesis in the testis. We aim to analyze the role of FSHR gene variants (single nucleotide polymorphisms (SNPs) in exon 10 (codon 307 and 680) and in the core promoter region (at position -29) and Ala189Val inactivating mutation) in Turkish infertile women. There were studies analyzing the effects of the SNPs in exon 10 (codon 307 and 680) and in the core promoter region (at position -29) of the FSHR gene on spermatogenesis, but to our knowledge, there were no studies analyzing the effects of these three SNP combinations on female fertility.

METHODS

In this study, the allelic, genotype, and haplotype frequency distributions of these three SNPs in the FSHR gene were analyzed in 102 infertile women and 99 unrelated healthy control individuals. The distribution of the polymorphisms was conformed by Hardy-Weinberg equilibrium test.

RESULTS

There were no statistical differences (P > 0.05) in the allele, genotype, and haplotype frequencies of the polymorphisms and FSH, luteinizing hormone (LH), estradiol (E2), and prolactin (PRL) levels between the infertile patients and the controls. However, a significant relation was found between 307 SNP GA genotype and FSH level ≥12. We did not find any homozygous or heterozygote mutations in infertile patients and healthy fertile controls.

CONCLUSION

The present study was the first study analyzing gma mutation and the polymorphism of the FSHR core promoter at position -29 alone and in combination with the two common SNPs in exon 10 in Turkish infertile women population. These findings indicate the significance of Ala307Thr GA genotype may be a predictive marker for poor ovarian reserve and infertility.

The genetics of premature ovarian failure: current perspectives

Premature ovarian failure (POF) is a common cause of infertility in women, characterized by amenorrhea, hypoestrogenism, and elevated gonadotropin levels in women under the age of 40. Many genes have been identified over the past few years that contribute to the development of POF. However, few genes have been identified that can explain a substantial proportion of cases of POF. The unbiased approaches of genome-wide association studies and next-generation sequencing technologies have identified several novel genes implicated in POF. As only a small proportion of genes influencing idiopathic POF have been identified thus far, it remains to be determined how many genes and molecular pathways may influence idiopathic POF development. However, owing to POF’s diverse etiology and genetic heterogeneity, we expect to see the contribution of several new and novel molecular pathways that will greatly enhance our understanding of the regulation of ovarian function. Future genetic studies in large cohorts of well-defined, unrelated, idiopathic POF patients will provide a great opportunity to identify the missing heritability of idiopathic POF. The identification of several causative genes may allow for early detection and would provide better opportunity for early intervention, and furthermore, the identification of specific gene defects will help direct potential targets for future treatment.

Aetiological coding sequence variants in non-syndromic premature ovarian failure: From genetic linkage analysis to next generation sequencing

Premature ovarian failure (POF) is a frequent pathology affecting 1-1.5% of women under 40 years old. Despite advances in diagnosing and treating human infertility, POF is still classified as being idiopathic in 50-80% of cases, strongly suggesting a genetic origin for the disease. Different types of autosomal and X-linked genetic anomalies can originate the phenotype in syndromic and non-syndromic POF cases. Particular interest has been focused on research into non-syndromic POF causative coding variants during the past two decades. This has been based on the assumption that amino acid substitutions might modify the intrinsic physicochemical properties of functional proteins, thereby inducing pathological phenotypes. In this case, a restricted number of mutations might originate the disease. However, like other complex pathologies, POF might result from synergistic/compensatory effects caused by several low-to-mildly drastic mutations which have frequently been classified as non-functional SNPs. Indeed, reproductive phenotypes can be considered as quantitative traits resulting from the subtle interaction of many genes. Although numerous sequencing projects have involved candidate genes, only a few coding mutations explaining a low percentage of cases have been described. Such apparent failure to identify aetiological coding sequence variations might have been due to the inherent molecular complexity of mammalian reproduction and to the difficulty of simultaneously analysing large genomic regions by Sanger sequencing. The purpose of this review is to present the molecular and cellular effects caused by non-synonymous mutations which have been formally associated, by functional tests, with the aetiology of hypergonadotropic non-syndromic POF. Considerations have also been included regarding the polygenic nature of reproduction and POF, as well as future approaches for identifying novel aetiological genes based on next generation sequencing (NGS).

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.

Are FSHR polymorphisms risk factors to premature ovarian insufficiency?

Premature ovarian insufficiency (POI) is an ovarian dysfunction characterized by increased FSH levels and amenorrhea before 40 years old. In recent years, the search for genetic causes of POI intensified and studies have been published relating the presence of mutations and polymorphisms in genes associated with development, recruitment and oocyte atresia. The aim of this study was to evaluate the presence of FSHR polymorphisms in our population and contribute with the elucidation of POI etiology. To achieve it, we have studied 100 patients with POI (G1), 60 patients with border line levels of FSH (G2) and 123 controls with regular menopause onset. Cytogenetic analysis of patients' samples and genotyping of Asn680Ser and Ala307Thr polymorphisms were performed in cases and controls. Cytogenetic analysis showed that 92% of G1 patients had normal karyotype, 4% presented polymorphic variants, 3% presented mosaic karyotype involving X chromosome. In G2, 91.6% had normal karyotype results, 3.2% displayed polymorphic variants, and 3.3% presented a mosaic karyotype involving X chromosome. Statistical comparison showed that the polymorphic allele of Ala307Thr polymorphism is more frequent in patients than in controls (G1: p < 0.001 and G2: p = 0.0259). This association has not been previously reported. We concluded that Ala307Thr polymorphism in FSHR can be potentially associated to POI development and can be considered as a screening marker in patients with ovarian failure signals.

Genetics of female infertility due to anomalies of the ovary and mullerian ducts

Genetic factors are pivotal in reproductive development and subsequent reproductive processes. If disturbed, infertility can occur. In the female, genetic factors affecting the ovary and the uterus are not uncommon causes of infertility. Terminal deletions on the X long arm and X short arm and X chromosomal mosaicism have long been accepted as causes of premature ovarian failure (POF). Responsible genes on the X have not yet elucidated. Attractive candidate genes for POF also exist on autosomes, and in over a dozen genes molecular perturbations are documented in non-syndromic POF. The most common single-gene cause of POF is premutation carriers for FMR1 (fragile X syndrome). As other candidate genes and additional ethnic groups are interrogated, the proportion of POF cases due to single-gene mutation will increase. Among uterine anomalies, incomplete mullerian fusion is most common. Increased recurrence risks for first-degree relatives confirm a role for genetic factors; interrogation of candidate genes is under way.

FSH receptor gene variants are rarely associated with premature ovarian failure

FSH receptor (FSHR) gene variants have been associated with premature ovarian failure (POF). Genomic DNA from New Zealand women with POF (n=80) and control women (n=80) was screened for variants in FSHR exons 7 and 10. FSHR exon 7 variants, including the c.566C>T Finnish founder mutation (p.Ala189Val), were not detected. Previously reported FSHR exon 10 polymorphisms were identified in both groups with similar allelic distributions. A novel heterozygous FSHR exon 10 variant c.1411A>T, p.Ile471Phe was observed in one woman with a family history of POF, but not her affected siblings. It is concluded that variants in exons 7 and 10 of FSHR are not frequently associated with the development of POF in the New Zealand population.

Follicle stimulating hormone receptor gene variants in women with primary and secondary amenorrhea

PURPOSE

This retrospective study was designed to analyze the FSHR gene variants in subjects with primary and secondary amenorrhea with hypergonadotropic hypogonadism.

MATERIALS AND METHODS

Eighty six women with primary or secondary amenorrhea and 100 normally cycling proven fertile women of Indian origin were retrospectively studied. These subjects were systematically screened for entire FSHR gene.

RESULTS

The frequency distribution of polymorphism at -29 position of FSHR gene is altered in women with primary and secondary amenorrhea as compared to controls. AA genotype at -29 position of FSHR gene seems to be associated with increased serum FSH levels in the study subjects. We have identified a novel homozygous mutation C(1723)T (Ala(575)Val) in one woman with primary amenorrhea.

CONCLUSIONS

Our findings suggest that increased serum FSH levels in subjects with primary amenorrhea correlated to FSHR genotype at position -29. We identified a novel homozygous mutation C(1723)T (Ala(575)Val) in a woman with primary amenorrhea.

Genes governing premature ovarian failure

Premature ovarian failure (POF) is unexplained amenorrhoea (>6 months), increased FSH (>20 IU/l) and LH occurring before 40 years. Several genes are reported as having significance in POF, including genes governing regulation of the hypothalamic-pituitary-ovarian axis, but their role in ovarian physiology is not known. Deletions or translocations in Xq arm have been found to be associated with POF, assuming presence of ovarian-related genes but ovary-related function of these genes is unclear. Several researchers have suggested specific loci on Xq critical region, POF1 and POF2 and genes DIA, FMR1 and FMR2. The understanding of ovarian physiology, its regulation and genes involved is important to explain the causes of POF. Some genes coordinate development of germ cell to primordial stage, e.g. GDF9, BMP15 and NGF, while others regulate development of further stages, such as FSH and LH. Mutation in these genes may lead to female infertility and are likely to be candidate genes for POF. Recently, association between blepharophimosis-ptosis-epicanthus inversus syndrome type 1 and POF has emerged as a possibility. Galactosaemia is also shown to be important in POF due to toxic effects of accumulated galactose or downstream products. Thus, understanding the role of several genes can be used for the appropriate genetic diagnosis, research and in the clinical practice of POF.

Genetically modified mouse models for premature ovarian failure (POF)

Premature ovarian failure (POF) is a complex disorder that affects approximately 1% of women. POF is characterized by the depletion of functional ovarian follicles before the age of 40 years, and clinically, patients may present with primary amenorrhea or secondary amenorrhea. Although some genes have been hypothesized to be candidates responsible for POF, the etiology of most of the cases is idiopathic, with the underlying causes still unidentified because of the heterogeneity of the disease. In this review, we consider some mutant mouse models that exhibit phenotypes which are comparable to human POF, and we suggest that the use of these mouse models may help us to gain a better understanding of the molecular mechanisms underlying POF in humans.

The haplotype of two FSHR polymorphisms in ovarian cancer--a potential role of ethnology in risk modification

OBJECTIVES

The precise role of gonadotropins in the carcinogenesis of epithelial ovarian cancer remains uncertain. Recently, the haplotype of two single nucleotide polymorphisms, Thr307Ala (rs6165) and Asn680Ser (rs6166), has been described as a risk factor for ovarian cancer in Chinese women. In this study we investigated the impact of this haplotype regarding the risk to develop ovarian cancer as well as possible effects upon the clinical course in a Caucasian patient sample.

SUBJECTS AND METHODS

Determination of genotypes in 115 patients with primary epithelial ovarian cancer and 115 age-matched controls was performed by Pyrosequencing for Thr307Ala and by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique for Asn680Ser.

RESULTS

Analysis of the genotypes revealed almost complete linkage disequilibrium of both SNPs. The distribution of genotypes was not statistically significant different between ovarian cancer patients and age-matched controls. Clinical parameters such as overall survival, CA12-5 elevation at primary diagnosis, age at diagnosis, FIGO stage, grading, and platinum resistance were not statistically significantly different regarding genotypes.

CONCLUSIONS

We could not confirm the FSHR Ala307-Ser680 haplotype as a risk factor for epithelial ovarian cancer in Caucasian women. Hence, the modification of tumor risk may be affected by the ethnology of the patient collective. We could not find any associations of clinical parameters or course of the disease with the different genotypes.

A distribution of two SNPs in exon 10 of the FSHR gene among the women with a diminished ovarian reserve in Ukraine

PURPOSE

To evaluate the association between phenotype and follicle stimulating hormone receptor (FSHR) genotype in women with ovarian dysfunction and patients with "poor response" to gonadotropin stimulation of ovulation.

METHODS

FSHR gene SNPs were analyzed by PCR and RFLP. "Poor responders" (ovarian dysfunction) group and "good responders" group constituted the study group. Normo-ovulatory women who gave birth to naturally conceived children formed control groups: under 35 years of age (control I) and over 35 years of age (control II).

RESULTS

The frequency of Ala307-Ser680/Ala307-Ser680 genotype was significantly more prevalent in the ovarian dysfunction group (26%) compared to the control I (7.7%) (P < 0.001) and a "good responders" group (12.5%) (P < 0.05); and in a "poor responders" group (33.3%) compared to a "good responders" group (P < 0.05), control I (P < 0.001) and control II (17.5%) (P < 0.05).

CONCLUSIONS

Our data shows the prevalence of the Ala307-Ser680/ Ala307-Ser680 genotype in the both groups of patients. The finding should have impact on the delineation of stimulation protocols.

Screening of follicle-stimulating hormone receptor gene in women with premature ovarian failure in southern Brazil and associations with phenotype

We investigated the presence of mutations/polymorphisms in the FSH receptor (FSHR) gene and their association with phenotype in women with premature ovarian failure (POF) in southern Brazil. Clinical and hormonal variables were determined in 36 46,XX women with primary or secondary amenorrhea before the age of 40 yr, FSH >40 IU/l and ovarian failure. DNA was isolated from peripheral leukocytes. Exons 6, 7, 9, and 10 of the FSHR gene were analyzed by PCR, restriction enzyme analysis, denaturing gradient gel electrophoresis, and direct sequencing. No inactivating mutations were found. Exon 10 had two polymorphisms, Ala307Thr and Ser680Asn (allelic frequency: 52.9 and 35.7%, respectively), which were not related to FSH, LH or estradiol serum levels. Ovarian size and small ovarian follicles on transvaginal sonography were not associated with FSHR genetic variants. In contrast, the last menstruation occurred significantly earlier in patients with the Ala307Thr polymorphism (A: age=33.3+/-7.1 yr vs T: 28.6+/-11.4 yr, p=0.04). In conclusion, we did not identify inactivating mutations in exons 6, 7, 9, and 10 of the FSHR gene. A high frequency of two polymorphisms that are in linkage disequilibrium was found in exon 10 of the FSHR gene. The presence of the Ala307Thr polymorphism may be associated with a more precocious onset of clinical disease.

Falência ovariana prematura: aspectos atuais

A falência ovariana prematura (FOP) acomete aproximadamente 1:1000 mulheres antes dos 30 anos, 1:250 em torno dos 35 anos e de 1:100 aos 40 anos. Manifesta-se como amenorréia primária ou amenorréia secundária, não podendo ser considerada definitiva em todas as pacientes, uma vez que a concepção espontânea pode ocorrer em até 5-10% das FOP. Na maioria dos casos apresenta-se na forma esporádica, pois apenas 5% apresentam história familial. Entre as causas conhecidas estão as alterações cromossômicas, dos genes ligados ao cromossomo X e cromossomos autossômicos, doenças autoimunes, alterações tóxicas e iatrogênicas. Com relativa freqüência, a causa etiológica não é obtida, sendo então denominada de idiopática. O diagnóstico da FOP é feito baseado na história clínica e níveis elevados do hormônio folículo estimulante (FSH), sendo posteriormente investigadas as causas mais específicas. O manejo clínico visa o suporte emocional, o tratamento hormonal com estrogênios e progestogênios, a abordagem da infertilidade e a prevenção de co-morbidades como a osteoporose e potencial maior risco cardiovascular.

Gonadotrophin resistance

Gonadotrophin resistance is caused by inactivating mutations in receptors (Rs) of the two gonadotrophins, i.e. luteinizing hormone (LH) and follicle-stimulating hormone (FSH), presenting as hypergonadotrophic hypogonadism and infertility/subfertility in both sexes. These conditions are extremely rare, but must be kept in mind upon differential diagnosis of disorders of sexual maturation, hypogonadism and infertility. In 46,XY individuals inactivation of LHR causes a disturbance in male-type sexual differentiation that ranges from male pseudohermaphroditism (complete lack of genital masculinization) to mild conditions such as cryptorchidism and hypospadias, depending on completeness of the receptor inactivation. In women, the phenotype is milder, presenting mainly as anovulatory amenorrhoea and hypo-oestrogenization. Inactivation of FSHR causes in otherwise normally masculinized men small testis size and variably reduced spermatogenesis, but not azoospermia or absolute infertility. In women the phenotype is more severe, with primary or early secondary amenorrhoea, arrested follicular maturation and anovulatory infertility. Incomplete forms with milder phenotype and partial responsiveness to FSH have also been described. Although gonadotrophin resistance is a very rare condition, its correct diagnosis is important for the selection of adequate treatment.

FSH receptor gene polymorphisms have a role for different ovarian response to stimulation in patients entering IVF/ICSI-ET programs

PURPOSE

To examine the frequency distribution of the Ser680Asn polymorphism of the follicle-stimulating hormone receptor (FSHR) gene in ovarian dysfunction (OD) infertile women, "poor responders" (PR) and "good responders" (GR).

METHODS

The hormonal profiles and treatment of all patients were analyzed and FSHR polymorphism was examined by PCR and RFLP. Women from all groups were classified as Asn/Asn, Asn/Ser, and Ser/Ser genotypes.

RESULTS

The frequency distribution of Ser/Ser, Asn/Ser and Asn/Asn variants in OD patients was 45.5, 22.7, and 31.8%, respectively. Day 3 FSH levels in OD and GR patients were higher in Ser/Ser and Asn/Asn subgroups. Asn/Ser carriers from OD and GR groups provided more follicles and oocytes compared to other allelic variants.

CONCLUSIONS

GR patients carry more often the Asn/Ser genotype. The latter is correlated with more follicles and oocytes in both OD and GR patients. The Ser/Ser variant might be related to higher serum FSH levels, while the Asn/Ser with lower.

Follicle-stimulating hormone receptor gene mutations are not evident in Greek women with premature ovarian failure and poor responders

BACKGROUND/AIMS

This clinical and molecular study aimed to investigate the presence of follicle-stimulating hormone (FSH) receptor gene mutations in women with premature ovarian failure (POF) and poor responders to in vitro fertilization treatment.

METHODS

DNA was extracted from blood samples for subsequent polymerase chain reaction (PCR). PCR was followed by restriction fragment length polymorphism and direct sequencing.

RESULTS

No inactivating mutations reported so far were identified in exons 6, 7, and 10 in women with POF and poor responders.

CONCLUSION

FSH receptor gene mutations are not frequent in Greek patients with POF as is the case in the rest of the world except for cases with ovarian dysgenesis in Finland.

Absence of follicle-stimulating hormone receptor activating mutations in women with iatrogenic ovarian hyperstimulation syndrome

OBJECTIVE

To analyze the FSH receptor gene in women with iatrogenic ovarian hyperstimulation syndrome (OHSS).

DESIGN

Clinical and molecular studies.

SETTING

University hospital and private clinic.

PATIENT(S)

Twenty-nine women who developed moderate or severe OHSS after ovulation induction for IVF. In addition, 50 fertile normal women were used as controls.

INTERVENTION(S)

Peripheral blood was used for DNA extraction. The exons 4, 7, 9, and 10 of the FSH receptor gene were amplified by polymerase chain reaction (PCR) followed by automatic direct sequencing.

MAIN OUTCOME MEASURE(S)

Hormonal results and automatic sequencing analysis.

RESULT(S)

Thirteen patients developed moderate OHSS and 16 patients developed the severe form of the syndrome. Automatic sequencing revealed no activating mutations in all patients studied. We found two known polymorphisms in linkage disequilibrium, Ala307Thr and Ser680Asn, in 79.3% of the patients (44.8% in heterozygous and 34.5% in homozygous state). These polymorphisms were found with similar frequency in the 50 normal fertile women.

CONCLUSION(S)

We conclude that the FSH receptor genotype did not play a significant role in the risk of iatrogenic OHSS in this cohort.

Screening of FSH receptor gene in Argentine women with premature ovarian failure (POF)

Diverse mutations in FSH-receptor (FSHR) gene have been described as possible cause of premature ovarian failure (POF). To investigate the presence of mutations and/or polymorphisms in FSHR gene, DNA from 20 POF, 5 of which were diagnosed as resistant ovary syndrome (ROS), and from 44 controls was isolated from peripheral lymphocytes. The complete coding sequence was analysed by PCR followed by SSCP, direct sequencing or restriction enzyme analysis. No mutations in FSHR gene were identified in the patients studied. The two already described polymorphisms in exon 10, A919G and A2039G, cosegregated in all the homozygous individuals, indicating that FSHR presents two isoforms: Ala307-Ser680 and Thr307-Asn680. OR results suggest that the 919G-2039G allelic variant or the homozygous genotype is not associated to disease risk. In addition, a heterozygous substitution T1022C (Val341Ala) was found in two control subjects. We suggest that mutations in FSHR gene are rare in women with POF in Argentine. Presence of a particular FSHR isoform does not appear to be associated with this disease.

Clinical and molecular analysis of human reproductive disorders in Brazilian patients

Several genes that influence the development and function of the hypothalamic-pituitary-gonadal-axis (HPG) have been identified. These genes encode an array of transcription factors, matrix proteins, hormones, receptors, and enzymes that are expressed at multiple levels of the HPG. We report the experience of a single Endocrinology Unit in the identification and characterization of naturally occurring mutations in families affected by HPG disorders, including forms of precocious puberty, hypogonadism and abnormal sexual development due to impaired gonadotropin function. Eight distinct genes implicated in HPG function were studied: KAL, SF1, DAX1, GnRH, GnRHR, FSHbeta, FSHR, and LHR. Most mutations identified in our cohort are described for the first time in literature. New mutations in SF1, DAX1 and GnRHR genes were identified in three Brazilian patients with hypogonadism. Eight boys with luteinizing hormone- (LH) independent precocious puberty due to testotoxicosis were studied, and all have their LH receptor (LHR) defects elucidated. Among the identified LHR molecular defects, three were new activating mutations. In addition, these mutations were frequently associated with new clinical and hormonal aspects, contributing significantly to the knowledge of the molecular basis of reproductive disorders. In conclusion, the naturally occurring genetic mutations described in the Brazilian families studied provide important insights into the regulation of the HPG.

Mechanisms of follicular dysfunction in 46,XX spontaneous premature ovarian failure

Approximately one half of young women who have 46,XX spontaneous premature ovarian failure have ovarian follicles remaining in the ovary. These follicles function intermittently and unpredictably, and pregnancies can occur in these women without intervention, even many years after the diagnosis. Clearly, the term "premature menopause" is an inaccurate term for this condition. At present, there are no proven therapies that will improve follicular function for these women. Inappropriate luteinization related to low follicle number seems to be a major mechanism of follicular dysfunction. Autoimmune oophoritis, although apparently an uncommon cause of follicular dysfunction in these women, nonetheless presents the opportunity to develop an effective therapy to restore fertility. Young women with 46,XX spontaneous premature ovarian failure benefit from the care of a sensitive clinician, one who is willing to spend a little more time informing them about the diagnosis and referring them to other sources of information. With appropriate medical management and emotional support provided by a sensitive clinician, most young women with 46,XX spontaneous premature ovarian failure will lead happy, healthy, and fulfilling lives.

Distribution and function of FSH receptor genetic variants in normal men

Follicle stimulating hormone (FSH) plays a key role in the maintenance of qualitatively and quantitatively normal spermatogenesis. It controls gamete development through Sertoli cells, via binding to its receptor. The influence and importance of FSH receptor (FSHR) variants on Sertoli cell function is not completely understood and remains to be investigated. In this retrospective study, we explored the impact and action of two distinct FSHR isoforms, Thr307/Asn680 and Ala307/Ser680, in a large group of men. This investigation includes 288 normal healthy men, 86 of whom were proven fathers previously studied, and 202 were newly recruited subjects. The FSHR polymorphism at position 680 was analyzed in the whole group, while position 307 was investigated in 150 subjects, both of them by single-stranded conformation polymorphism (SSCP) gel electrophoresis. The distribution frequency for position 680 was 29% for the Asn/Asn, 52% for the Asn-Ser, 19% for the Ser-Ser variant, and for position 307, 27% for the Thr-Thr, 55% for the Ala-Thr, 18% for the Ala-Ala, respectively. Polymorphism combinations that were different from Thr307/Asn680 - Ala307/Ser680 were found in four subjects. When subjects were grouped according to genotype at position 680, no significant differences between basal FSH, testosterone, inhibin B levels and semen parameters were found. This clinical finding demonstrates that, differently from females, in whom a significant correlation between FSHR polymorphism and basal FSH levels was found, the FSHR genotype has no influence on clinical parameters in males.

Genetic approaches to unraveling reproductive disorders: examples of bedside to bench research in the genomic era

Despite the rapid advances in medical genetics, many clinicians and investigators remain unaware of the general approaches that can be used to map genes. Although there are specific challenges to using genetic approaches in reproductive medicine, the following report summarizes mapping efforts for three diseases: adrenal hypoplasia congenita, hypergonadotropic ovarian failure, and polycystic ovary syndrome. The themes of rare and novel phenotypes, genetically homogenous populations, and genotype/phenotype correlations are emphasized.

A Novel mutation in the FSH receptor inhibiting signal transduction and causing primary ovarian failure

Inactivating mutations of the FSH receptor (FSHR) are known to cause ovarian failure with amenorrhea and infertility in women. The first mutation identified in the FSHR gene was a missense mutation (566C-->T, predicting Ala189Val transition) found in several Finnish patients with primary amenorrhea due to ovarian failure. Only five additional, partially or totally inactivating, mutations of the FSHR have been reported. Here, we report a novel FSHR mutation, 1255G-->A, in a Finnish female with primary amenorrhea. The patient was a compound heterozygote for two mutations in the FSHR gene: 566C-->T, the Finnish founder mutation, and 1255G-->A, a previously unidentified mutation. The new mutation is located in exon 10 in the second transmembrane stretch of the FSHR, and it predicts an Ala419Thr change in the protein structure. In functional testing, the mutation was shown to have minimal effect on ligand binding capacity and affinity, but it almost totally abolished the cAMP second messenger response. Neither of the two FSHR mutations (566C-->T or1255G-->A) was identified in 40 other Finnish patients with premature ovarian failure. Based on this and previous studies, FSHR mutations remain a rare cause of ovarian failure.

Receptores acoplados à proteína G: implicações para a fisiologia e doenças endócrinas

A maioria dos hormônios polipeptídicos e mesmo o cálcio extracelular atuam em suas células-alvo através de receptores acoplados à proteína G (GPCRs). Nos últimos anos, tem sido freqüente a identificação e associação causal de mutações em proteínas G e em GPCRs com diversas endocrinopatias, como diabetes insipidus nefrogênico, hipotiroidismo familiar, puberdade precoce familiar no sexo masculino e nódulos tiroidianos hiperfuncionantes. Nesta revisão, abordamos aspectos referentes ao mecanismo de transdução do sinal acoplado à proteína G, e descrevemos como mutações em GPCRs podem levar a algumas doenças endócrinas. Finalmente, comentamos a respeito das implicações diagnósticas e terapêuticas associadas com o maior conhecimento dos GPCRs.

No evidence of mutations in the follicle-stimulating hormone receptor gene in Mexican women with 46,XX pure gonadal dysgenesis

In the ovary FSH is necessary for normal follicular development, binding to its receptor (FSHR) that pertains to the superfamily of G-protein coupled receptors. In the FSHR gene, which consists of 10 exons, an homozygous mutation was reported in six Finnish families with gonadal dysgenesis; whereas two isolated French patients exhibited compound heterozygous mutations. Several groups, however, have searched for FSHR mutations, although in most cases the gene has been studied partially, not finding any genetic abnormalities in German, English, North American or Brazilian women. We performed direct sequencing of all 10 exons of the FSHR gene in seven sporadic patients and two sisters with 46,XX pure gonadal dysgenesis, to investigate the cause of their disorder. No heterozygous or homozygous mutant alleles were present in any of the patients. Although the number of patients evaluated was small, considering all the other previous reports, it seems that except in the Finnish population, the proportion of women with mutations in the encoding region of this gene is very low. Other possibilities for the presence of 46,XX gonadal dysgenesis, such as defects in the regulatory regions of the FSHR gene promoter, in the untranslated regions of exons 1 and 10, and within introns, or the existence of other genes likely to be important for normal ovarian function on the X chromosome or on autosomes, should be considered. In contrast with other studies, we did not find polymorphisms of the FSHR gene, indicating that apparently in Mexicans this gene is not highly polymorphic.

Mutations of gonadotropins and gonadotropin receptors: elucidating the physiology and pathophysiology of pituitary-gonadal function

The recent unraveling of structures of genes for the gonadotropin subunits and gonadotropin receptors has provided reproductive endocrinologists with new tools to study normal and pathological functions of the hypothalamic-pituitary-gonadal axis. Rare inactivating mutations that produce distinctive phenotypes of isolated LH or FSH deficiency have been discovered in gonadotropin subunit genes. In addition, there is a common polymorphism in the LHbeta subunit gene with possible clinical significance as a contributing factor to pathologies of LH-dependent gonadal functions. Both activating and inactivating mutations have been detected in the gonadotropin receptor genes, a larger number in the LH receptor gene, but so far only a few in the gene for the FSH receptor. These mutations corroborate and extend our knowledge of clinical consequences of gonadotropin resistance and inappropriate gonadotropin action. The information obtained from human mutations has been complemented by animal models with disrupted or inappropriately activated gonadotropin ligand or receptor genes. These clinical and experimental genetic disease models form a powerful tool for exploring the physiology and pathophysiology of gonadotropin function and provide an excellent example of the power of molecular biological approaches in the study of pathogenesis of diseases.

Mutation analysis of the follicle-stimulating hormone receptor gene in girls with gonadotropin-independent precocious puberty resulting from autonomous cystic ovaries

OBJECTIVE

To search for germline activating mutations of the FSH receptor in girls with gonadotropin-independent precocious puberty.

DESIGN

Molecular studies in human tissue.

SETTING

Four girls with polycystic ovaries and gonadotropin-independent isosexual precocious puberty without clinical and molecular features of McCune-Albright syndrome.

INTERVENTION(S)

Peripheral blood was used for DNA extraction. The alpha-subunit of the Gs gene and the entire exon 10 of FSH receptor gene were amplified by polymerase chain reaction (PCR). Gs-alpha mutations characteristic of McCune-Albright syndrome were excluded by denaturating gradient gel electrophoresis (DGGE) and allele-specific PCR. Exon 10 of the FSH receptor gene was analyzed by DGGE and direct sequencing.

MAIN OUTCOME MEASURE(S)

Results of DGGE and direct sequencing.

RESULT(S)

No germline activating mutations were detected in exon 10 of our patients. Instead, two previously described polymorphisms were found, leading to the substitution of alanine for threonine at position 307 and of serine for asparagine at position 680 of the FSH receptor molecule.

CONCLUSION(S)

Germline activating mutations were not found in exon 10 of the FSHR gene in any of our patients. Further studies, preferably in ovarian tissue, will be required to exclude the presence of somatic activating mutations of the FSH receptor in these patients.

Follicle-stimulating hormone ligand and receptor mutations, and gonadal dysfunction

In contrast to the general contention, infertility can be an inherited condition. Some of the genetic causes of male and female infertility have turned out to be due to inactivating mutations in the gonadotropin and gonadotropin receptor genes. The topic of the present text is to review current knowledge on mutations affecting the function of follicle-stimulating hormone (FSH). This gonadotropin, by binding to its specific G protein-coupled cell membrane receptor (FSHR), is important for normal gonadal function. Mutations affecting gonadotropin genes are extremely rare, but recent genetic studies have revealed that the pathogenesis of subfertility or infertility can be due to mutations in the FSH receptor (FSHR) gene. While mutations affecting FSHR are sporadic, polymorphism of the FSHR gene seems to be a common phenomenon. To date, six inactivating and only one activating mutation have been detected in the FSHR gene. In contrast to LHR gene, the majority of these mutations affect the extracellular domain of the receptor. Together with animal models using the transgenic and knock-out approaches, systematic analysis of alterations in the FSHR gene increases our knowledge on the structure and function of the FSHR and demonstrates that the integrity of each FSHR segment is required for proper expression of the fully active protein and for normal gonadal function. Mutations in the FSHR gene have different consequences in the reproductive function depending on the sex of the patient: while normal ovarian function is critically dependent on FSH, male fertility is possible with minimal or absent FSH action.

Mutation screening and isoform prevalence of the follicle stimulating hormone receptor gene in women with premature ovarian failure, resistant ovary syndrome and polycystic ovary syndrome

OBJECTIVE

To determine whether mutations in the FSH receptor gene are associated with premature ovarian failure (POF) or resistant ovary syndrome (ROS) in women in the UK. To determine whether an allelic variant of the FSH receptor gene affects fertility parameters in women with polycystic ovary syndrome (PCOS).

DESIGN

A mutation screen using DNA from women with POF and ROS. Restriction digest of amplified DNA from women with POF, ROS, PCOS and controls to determine allelic variant status. Fertility parameters were compared between allelic variant subgroups of women with PCOS.

PATIENTS

The study population comprised 49 women with POF, 5 with ROS, 93 with PCOS and 51 controls.

MEASUREMENTS

In women with PCOS, fertility and menstrual status was recorded and serum FSH and ovarian volume were measured.

RESULTS

No mutation of the FSH receptor gene was found in women with POF or ROS. The allelic variant Thr307/Ser680 was found to be similarly prevalent in all study groups. The Thr307/Ser680 variant was found to have no phenotype in terms of fertility parameters in women with PCOS.

CONCLUSIONS

Mutations of the FSH receptor gene are rare in women with premature ovarian failure or resistant ovary syndrome in the UK. Polymorphisms of the FSH receptor gene do not appear to have pathophysiological significance with regard to ovarian function.

Menstrual disorders and infertility caused by inactivating mutations of the luteinizing hormone receptor gene

OBJECTIVE

To review clinical findings, hormone levels, and DNA analyses in genetic males and females with inactivating mutations of the LH receptor gene.

DESIGN

Review of reported cases.

SETTING

A university hospital.

PATIENT(S)

Genetic males and females with inactivating mutations of the LH receptor gene.

RESULT(S)

The clinical presentation in genetic males ranged from female genitalia to male genitalia with micropenis caused by Leydig cell hypoplasia. Genetic females presented with amenorrhea or oligomenorrhea, enlarged cystic ovaries, and infertility. Both males and females had elevated LH levels and LH/FSH ratios. Sequencing of genomic DNA revealed homozygous or compound heterozygous deletions, nonsense mutations, or missense mutations in the LH receptor gene.

CONCLUSION(S)

This study of patients with inactivating mutations of the LH receptor indicates that in genetic males, the action of hCG and LH is necessary for the normal development of primary and secondary sexual characteristics. In contrast, secondary sexual characteristics develop in genetic females in the absence of LH action, but they fail to ovulate.