Mutation in the follicle-stimulating hormone receptor gene causes hereditary hypergonadotropic ovarian failure

Premature ovarian failure: a review

OBJECTIVES

To present an updated review on the etiology, consequences and management of premature ovarian failure.

DESIGN

A search of the English language literature using the Cochrane Library database and Medline 1966-2006, with a hand search of the references.

CONCLUSION

Premature ovarian failure is defined as the occurrence of amenorrhea, hypergonadotropinemia and estrogen deficiency in women under the age of 40 years, with the prevalence being 0.9-1.2%. In the majority of cases, the etiology is unknown, but known causes include chemotherapy, radiotherapy, surgery, genetic disorders, particularly involving the X chromosome, associations with autoimmune diseases, infections, smoking and other toxins. The three critical issues of management in these women are the effect of the diagnosis on the psychological health of the patient, the consequent infertility and the long- and short-term effects of estrogen deficiency arising from ovarian decline. Promising methods of screening for premature ovarian failure are being developed.

Mutation analysis of NANOS3 in 80 Chinese and 88 Caucasian women with premature ovarian failure

NANOS3 encodes an RNA-binding protein and has a conserved function in germ cell development. Our objective was to investigate whether mutations in NANOS3 were present in Chinese and Caucasian women with premature ovarian failure. A known synonymous single-nucleotide polymorphism (rs 2016163) in exon 1 was identified through sequencing 80 Chinese and 88 Caucasian women with premature ovarian failure. No additional single-nucleotide polymorphisms or mutations were found in exons encoding for NANOS3. Our findings suggest that mutations in NANOS3 exons are rare in both Chinese and Caucasian women with premature ovarian failure.

Presence or absence of menstruation in young girls

Menstruation is a periodic discharge of sanguinous fluid and sloughing of the uterine lining in the female. It is an event characteristic of the reproductive cycle in humans and most subhuman primates and has no known biological function. However, it is an integral part of a woman's experience throughout her reproductive life. This article will examine menstrual patterns and concerns in young girls. The section on absent menstruation will concentrate on premature ovarian failure.

[Follicle-stimulating hormone receptor polymorphism and ovarian function]

The FSH receptor presents several polymorphisms. Two of them, located at codon 307 and 680, are the most frequent. Threonine can be substituted by alanine at position 307 and serine can be substituted by asparagine at position 680. The two most frequent allelic combinations are Thr(307) -Asn (680) (60%) and Ala(307) -Ser (680) (40%). As the allelic variants at codon 307 and 680 are almost invariably associated, most of the studies assessed only one codon (680) and classified the women as homozygous (Ser/Ser ou Asn/Asn) or heterozygous (Asn/Ser). Several studies aimed to correlate the follicle-stimulating hormone receptor polymorphism and ovarian function. Women homozygous for the Ser (680) variant have higher follicular FSH levels and longer follicular phase length, which suggest a lower sensitivity to FSH. The FSH receptor genotype would also influence the sensitivity to exogenous FSH: as regards ovarian stimulation, higher recombinant FSH doses are needed for Ser/Ser homozygous women. The analysis of polymorphism in women with premature ovarian failure did not show a link with any particular allelic variant. In women with polycystic ovaries, the distribution of the allelic variants greatly varies from one study to another.

Mechanisms of disease: Mutations of G proteins and G-protein-coupled receptors in endocrine diseases

G proteins and G-protein-coupled receptors (GPCRs) mediate the effects of a number of hormones. Genes that encode these molecules are subject to loss-of function or gain-of-function mutations that result in endocrine disorders. Loss-of-function mutations prevent signaling in response to the corresponding agonist and cause resistance to hormone actions, which mimics hormone deficiency. Gain-of-function mutations lead to constitutive, agonist-independent activation of signaling, which mimics hormone excess. Disease-causing mutations of GPCRs have been identified in patients with various disorders of the pituitary-thyroid, pituitary-gonadal and pituitary-adrenal axes, and in those with abnormalities in food intake, growth, water balance and mineral-ion turnover. The only mutational changes in G proteins unequivocally associated with endocrine disorders occur in GNAS (guanine nucleotide-binding protein G-stimulatory subunit alpha, or G(s)alpha). Heterozygous loss-of-function mutations of GNAS in the active, maternal allele cause resistance to hormones that act through G(s)alpha-coupled GPCRs, whereas somatic gain-of-function mutations cause proliferation of endocrine cells that recognize cyclic AMP as a mitogen. The study of mutations in G proteins and GPCRs has already had major implications for understanding the molecular basis of rare endocrine diseases, as well as susceptibility to multifactorial disorders that are associated with polymorphisms in these genes.

La signalisation FSH a-t-elle un sexe ?

FSH is the main endocrine control of mammalian reproduction. FSH triggers somatic cells of the gonads which support germ cells metabolically, i.e. Sertoli cells of the seminiferous tubules, and granulosa cells harboring the oocyte, within the ovarian follicle. FSH leads to similar biological responses in both cell types since it stimulates proliferation and differentiation, according to the developmental stage. However, FSH receptor knock-out female mice are infertile, unlike male mice. Hence, FSH is not equally important in both sexes. Nevertheless, does FSH induce distinct signalling mechanisms in its target cells ? Here, we compare the signalling mechanisms induced by FSH in ovarian and testicular physiology.

FSH receptor genotype is associated with pregnancy but not with ovarian response in IVF

Two very common single nucleotide polymorphisms at positions 307 and 680 in exon 10 of the FSH receptor gene have been associated with ovarian response in IVF. This observational study evaluated the role of the FSH receptor genotype in the prediction of poor response and clinical pregnancy in IVF in comparison with other markers, such as age, basal FSH, anti-Müllerian hormone and antral follicle count. In addition, the in-vitro cAMP response towards recombinant FSH in cultured granulosa cells of patients with different FSH receptor genotypes was determined. A total of 105 IVF patients undergoing ovarian stimulation in a long suppression protocol were included in the study. The ovarian response was comparable between patients with different FSH receptor genotypes. Patients with polymorphism Ser/Ser had implantation and pregnancy rates that were three times higher compared with patients with polymorphism Asn/Asn. FSH receptor genotype was not associated with a poor response in IVF, but showed a positive association with pregnancy, independent of age. There was no difference in cAMP production in cultured granulosa cells of patients with different FSH receptor genotypes (n=62). It is concluded that FSH receptor genotype is associated with pregnancy in IVF, but not with ovarian response.

Mouse models for gonadotropins: a 15-year saga

Pituitary gonadotropins FSH and LH are heterodimeric glycoproteins consisting of a common alpha and a hormone-specific beta subunit that are non-covalently linked. Both these hormones bind G-protein coupled receptors and regulate multiple processes in the gonads. Advances in the past two decades in manipulating the mouse genome by random and site-specific mutagenesis have been invaluable to our understanding of the biology of gonadotropins. Using these transgenic and gene targeting approaches, both gain-of-function transgenic as well as knockout mice lacking the hormone-specific gonadotropin subunits, and hence functional dimeric hormones were generated. Furthermore, knockout mice lacking regulators of gonadotropin production have also been characterized. These mice are useful to delineate the distinct in vivo biological roles of FSH and LH, and provide valuable genetic tools to study the signaling mechanisms within the gonads. Here, I will discuss our work on different ways to manipulate gonadotropin ligand function in the mouse.

The tale of follitropin receptor diversity: a recipe for fine tuning gonadal responses?

The original concept (dogma) of a single FSH receptor entity coupling to G(s) protein to activate adenylate cyclase and producing cAMP as second messenger appears inadequate to explain pleiotropic actions of the hormone. The identification and expression of alternatively spliced gonadotropin receptors, suggest that alternative splicing could serve as a mechanism for creating receptor diversity. Studies focused on sheep and mouse gonadal tissues show that the single large gene of approximately 250kb is a modular structure whose pre-mRNA undergoes alternative splicing creating several subtypes (at least four FSH-R1 to R4 identified to date). With segments of the N-terminus that are identical different topographies are generated by differing carboxyl termini. The same gene thus produces receptor types with different motifs that can display dominant positive, dominant negative, growth factor/cytokine type and potentially soluble binding protein features. Functional relevance is shown by modulation of receptor variants during hormonal stimulation. Presence of equivalent segments of the gene in the human and bovine suggests conservation and predicts similarity in structures and function. Thus, the complex cellular biology of follitropin receptors that may interact differently with polymorphic forms (glycosylation variants) of FSH represents an intricate scheme to regulate hormone signaling.

Genetic analysis of the follicle stimulating hormone receptor gene in women with polycystic ovary syndrome

This study was designed to assess the relationship between mutations in the FSH receptor (FSHr) gene and polycystic ovary syndrome (PCOS) in Italian women. The study population included 50 patients with PCOS and 50 age- and body mass index (BMI)-matched controls. A complete anthropometrical, hormonal and pelvic ultrasonographic evaluation was performed in all subjects. Genomic DNA was extracted from peripheral lymphocytes and then each exon of the FSHr gene was amplified by PCR. The mutation identified was cloned and the functional properties were studied after transient expression in COS-7 cells. Direct sequencing of exons 1-10 of the FSHr gene revealed the presence of a heterozygous AAT/ATT mutation affecting the isoleucine residue at position 411, which was replaced by an asparagine, in the second transmembrane segment (I411N). This mutation was only found in one woman with PCOS and not in her parents. This mutation was not present in 50 age and BMI controls and in another 150 women not affected by PCOS. The functional study after transient expression in COS-7 cells revealed that this I411N had similar functional characteristics with respect to the wild type FSHr (wtFSHr). Genetic analyses of polymorphisms in the human FSHr gene were also performed. All 50 women with PCOS harbored the A307T polymorphic variant, 56% harbored N680S, 30% S680S and 14% N680N polymorphisms. In conclusion, the present study demonstrates that mutations of the FSHr gene are rare in Italian women. The only mutation that we found does not appear to have any pathophysiological significance in PCOS.

L’insuffisance ovarienne prématurée

Premature ovarian failure (POF) is defined by at least four months of amenorrhea with elevated gonadotropins (usually above 40 UI/L) detected on two occasions a few weeks apart, in a woman before the age of 40. It occurs in 1 out of 10,000 in women below the age of 20, 1/1,000 below 30 and 1% in women before the age of 40. In 80% of POF cases, the etiology is unknown, except for Turner syndrome. The different etiologies identified are 1) iatrogenic following chemotherapy and/or radiotherapy, 2) autoimmune, 3) viral, 4) genetic (RFSH, FOXL2, FRAXA, BMP15, GDF9, GALT, 17 hydroxylase...). Management of these patients includes hormone replacement therapy in order to avoid an increase in cardiovascular risk and osteoporosis related to hypoestrogenism. Infertility is common, as only 3 to 10% of the patients will have natural conception. When fertility is desired, women with POF should be oriented towards oocyte donation centers. Research is currently performed in order to identify new genes involved in POF.

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.

Mutational analysis of BMP15 and GDF9 as candidate genes for premature ovarian failure

Mutational screening of the bone morphogenetic protein 15 (BMP15) and growth differentiation factor 9 (GDF9) genes in a population with premature ovarian failure (POF) identified no new mutations. However, three single nucleotide polymorphisms in the BMP15 gene, two in the 5' untranslated region (31T>G and 71C>G) and another in exon 1 (387G>A), were found to be common in both POF and control groups.

Current evaluation of amenorrhea

Amenorrhea is the absence or abnormal cessation of the menses. Primary and secondary amenorrhea describe the occurrence of amenorrhea before and after menarche, respectively.

Premature ovarian failure

PURPOSE OF REVIEW

To summarize current knowledge about premature ovarian failure (POF) with an emphasis on recent developments regarding its management.

RECENT FINDINGS

The incidence of POF is increasing largely due to improved survival rates of cancer patients treated with radiation and chemotherapy. Delayed diagnosis and management of POF leads to suboptimal outcomes. Anticipation and early detection of this condition in high-risk women by means of ovarian function testing, followed by early institution of appropriate management could improve outcomes. Choice of strategies should vary depending on the age of onset, associated symptoms and fertility aspirations of the individual, and should change with the patient's advancing age.

SUMMARY

Early assessment of the individual's risk of developing POF, development of a strategic management plan, and timely commencement of infertility and hormone deficiency treatment, together with counselling in an integrated management plan should improve both the short and long-term health of those with POF.

Inactivating mutations of G protein-coupled receptors and diseases: Structure-function insights and therapeutic implications

Since the discovery of the first rhodopsin mutation that causes retinitis pigmentosa in 1990, significant progresses have been made in elucidating the pathophysiology of diseases caused by inactivating mutations of G protein-coupled receptors (GPCRs). This review aims to compile the compelling evidence accumulated during the past 15 years demonstrating the etiologies of more than a dozen diseases caused by inactivating GPCR mutations. A generalized classification scheme, based on the life cycle of GPCRs, is proposed. Insights gained through detailed studies of these naturally occurring mutations into the structure-function relationship of these receptors are reviewed. Therapeutic approaches directed against the different classes of mutants are being developed. Since intracellular retention emerges as the most common defect, recent progresses aimed at correcting this defect through membrane permeable pharmacological chaperones are highlighted.

Mutation of the Follicle-Stimulating Hormone Receptor Gene 5′-Untranslated Region Associated With Female Hypertension

Inactivating mutations in the follicle-stimulating hormone receptor (FSHR) gene have been reported to cause hereditary hypergonadotropic ovarian failure. It has been found recently that the FSHR knockout mouse exhibits hypertension. The aim of the present study was to investigate the association between polymorphisms in the human FSHR gene and essential hypertension (EH) by using single nucleotide polymorphisms (SNPs). We selected 5 SNPs in the gene (rs1394205, rs2055571, rs11692782, rs1007541, and rs2268361) and performed 2 genetic case-control studies in different populations. A confirmative case-control study was performed using 1035 EH patients and 1058 age-matched controls. Transcriptional activities were measured with a luciferase assay system. The first case-control study found that the A allele of rs1394205 was significantly higher in EH females (P=0.010). In addition, in the confirmative case-control study, there was a significant difference for this SNP between female normotensive subjects (44.5%) and EH patients (50.7%) (P=0.043). Multiple logistic regression analysis in female subjects also revealed a significant association of subjects with the A allele of rs1394205 with EH (P=0.033), with the odds ratio calculated as 1.68 (95% CI: 1.04 to 2.73). Transcriptional activity of the A allele was 56+/-8% (mean+/-SD) of that observed for the G-type allele (P=0.001). Serum estradiol levels were significantly lower in patients with the A/A genotype than in patients without the A/A genotype (P=0.004). The SNP in the 5'-untranslated region of the FSHR gene affects levels of transcriptional activity and is a susceptibility mutation of EH in women.

The genetic basis of premature ovarian failure

Premature ovarian failure (POF) is a common condition, affecting approximately 1:100 women. It is characterised by amenorrhea, hypoestrogenism, and elevated gonadotrophin levels in women under the age of 40. It is often an unexpected and distressing diagnosis, which coincides with infertility and menopausal symptoms. There is a well recognised genetic basis to the development of POF. Our laboratory has identified several candidate genes associated with POF.

Follicle-stimulating hormone receptor gene polymorphism and ovarian responses to controlled ovarian hyperstimulation for IVF-ET

This study was performed to investigate the association between FSH receptor (FSHR) gene polymorphism at position 680 and the outcomes of controlled ovarian hyperstimulation (COH) for in vitro fertilization and embryo transfer (IVF-ET) in Korean women. Two hundred and sixty-three patients under 40 years of age who underwent IVF-ET procedures were included in this study. Patients with polycystic ovary syndrome, endometriosis, or a previous history of ovarian surgery were excluded. Following extraction of genomic DNA, the FSHR polymorphism at position 680 was determined by polymerase chain reaction and restriction fragment length polymorphism analysis. The FSHR genotype distribution was 41.8% for Asn/Asn, 45.6% for Asn/Ser, and 12.5% for Ser/Ser FSHR genotype groups. Although there was no difference among the three genotype groups in terms of the age and infertility diagnosis of study subjects, the basal levels of FSH (day 3) were significantly different [5.7 +/- 0.3 IU/l (mean+/-SEM), 6.0 +/- 0.3 IU/l, and 8.2 +/- 0.9 IU/l for Asn/Asn, Asn/Ser, and Ser/Ser groups, respectively. The Ser/Ser group tended to require a higher dose of gonadotropins for COH, and tended to show lower serum estradiol levels at the time of hCG administration than the other two groups, though these differences did not reach statistical significance. The numbers of oocytes retrieved tended to be different for the three groups (9.6 +/- 0.6, 10.2 +/- 0.6, and 7.9 +/- 0.8 for Asn/Asn, Asn/Ser, and Ser/Ser groups, respectively). Clinical pregnancy rate was significantly higher in Asn/Asn, compared to the others (45.7 vs. 30.5%, P=0.013). The homozygous Ser/Ser genotype of FSHR polymorphism at position 680 may be associated with a reduced ovarian response to COH for IVF-ET, while Asn/Asn genotypes showed a higher pregnancy rate.

Mutations along the pituitary-gonadal axis affecting sexual maturation: novel information from transgenic and knockout mice

During the last 10 years, numerous activating and inactivating mutations have been detected in the genes encoding the two gonadotrophins, luteinising hormone (LH) and follicle-stimulating hormone (FSH), as well as their cognate receptors (R), LHR and FSHR. Because activation of the hypothalamic-pituitary-gonadal axis is a crucial event in the onset and progression of puberty, mutations affecting gonadotrophin action have major influence on this developmental process. Many of the phenotypic effects observed have been expected on the basis of the existing information about gonadotrophin action (e.g. delayed puberty), but also many unexpected findings have been made, including the lack of phenotype in women with activating LHR mutations, and the discrepancy in phenotypes of men with inactivating mutations of FSHbeta (azoospermia and infertility) and FSHR (oligozoospermia and subfertility). Some of the possible mutations, such as inactivating LHbeta and activating FSHR mutations in women, have not yet been detected. Genetically modified mice provide relevant phenocopies for the human mutations and serve as good models for studies on molecular pathogenesis of these conditions. They may also predict phenotypes of the mutations that have not yet been detected in humans. We review here briefly the effects of gonadotrophin subunit and receptor mutations on puberty in humans and contrast the information with findings on genetically modified mice with similar mutations.

X-linked premature ovarian failure: a complex disease

Involvement of the X chromosome in premature ovarian failure was demonstrated by the relatively frequent chromosomal rearrangements in patients, but the requirement of two X chromosomes for ovarian function was quite unexplained until recently. Review of the data on chromosomal rearrangements suggests that several genes along the X chromosomes contribute to ovarian function. In most instances, no single X chromosome gene has a causative role in premature ovarian failure, and the phenotype is likely to derive from the additive effect of X-linked and non-X-linked factors. Recent data on a small group of balanced X-autosome translocations showed that X-linked premature ovarian failure might also be caused by a different mechanism, namely position effect of the X chromosome on non-X-linked genes, and suggest a peculiar organization of the X chromosome during oogenesis.

Investigation of the human stem cell factor KIT ligand gene, KITLG, in women with 46,XX spontaneous premature ovarian failure

OBJECTIVE

To investigate mutations in the human KIT ligand gene (KITLG) gene as a mechanism of 46,XX spontaneous premature ovarian failure. The human KIT ligand gene, known also as human stem cell factor, is the ligand of the c-kit transmembrane tyrosine kinase receptor (KIT). This ligand-receptor interaction is known to play important roles in mouse germ cell migration and proliferation.

DESIGN

Cross-sectional study.

SETTING

Clinical research center.

PATIENT(S)

Forty women with 46,XX spontaneous premature ovarian failure.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Single-stranded conformational polymorphism analysis and DNA sequencing.

RESULT(S)

We found one nucleotide change of the KITLG coding region (811G-->T) that led to an alteration of the amino acid composition of the KITLG protein in one Caucasian patient (Asp210Tyr). However, we found the same alteration in two normal control Caucasian samples. Three nucleotide substitutions were found in the noncoding exon of KITLG (exon 10). We also identified two intronic polymorphisms. Thus, we did not identify a single significant mutation in the coding region of the KITLG gene in any of 40 patients (upper 95% confidence limit is 7.2%).

CONCLUSION(S)

Mutations in the coding regions of the KITLG gene appear not to be a common cause of 46,XX spontaneous premature ovarian failure in North American women.

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.

Maintenance of Spermatogenesis by the Activated Human (Asp567Gly) FSH Receptor During Testicular Regression Due to Hormonal Withdrawal1

The first activating mutation of the FSH receptor (FSHR*D567G) was identified in a gonadotropin-deficient hypophysectomized man who exhibited persistent spermatogenesis and fertility with only androgen replacement. We have determined the ability of FSHR* activity to maintain spermatogenesis and/or steroidogenesis during gonadotropin and androgen deprivation in mature transgenic FSHR* mice (Tg(Abpa-FSHR*D567G)1Cmal), hereafter referred to as Tg-FSHR* mice. Testes of untreated adult Tg-FSHR* males were equivalent in weight to nontransgenic controls but exhibited increased total Sertoli cell (24%) and spermatogonia (34%) numbers and nonsignificantly elevated spermatocyte-spermatid numbers (13%-17%). During sustained GNRH1 agonist treatment that markedly reduced (96%-98%) serum LH and testosterone (T) and decreased serum FSH (68%-72%), the testes of GNRH1 agonist-treated Tg-FSHR* mice remained significantly larger than treated nontransgenic controls. After 4 wk of gonadotropin suppression, Sertoli cell numbers were reduced in Tg-FSHR* testes to levels comparable with nontransgenic testes, whereas spermatogonia numbers were maintained at higher levels relative to nontransgenic testes. However, after 8 wk of GNRH1 agonist treatment, the total spermatogonia, spermatocyte, or postmeiotic spermatid numbers were reduced to equivalent levels in Tg-FSHR* and nontransgenic mice. FSHR* effects were further examined in gonadotropin-deficient hypogonadal Gnrh1hpg/Gnrh1hpg (Gnrh1(-/-)) mice during testicular regression following withdrawal of T after maximal T-stimulated spermatogenesis. After 6 wk of T withdrawal, spermatogonia, spermatocyte, and postmeiotic spermatid numbers in Tg-FSHR* Gnrh1(-/-) testes decreased to levels found in untreated Tg-FSHR* Gnrh1(-/-) testes. Basal serum T levels in untreated Tg-FSHR* Gnrh1(-/-) males were 2-fold higher than Gnrh1(-/-) controls, but following T treatment/withdrawal, serum T and epididymal weights declined to basal levels found in nontransgenic Gnrh1(-/-) mice. Therefore, FSHR* was unable to sustain circulating T or androgen-dependent epididymal size or postmeiotic spermatogenic development. We conclude that FSHR* activity enhances Sertoli and spermatogenic development in normal testes but has limited ability to maintain spermatogenesis during gonadotropin deficiency, in which the testicular response provided by the FSHR*D567G mutation resembled typical FSH-mediated but not steroidogenic activity.

Mutational analysis of the betaglycan gene-coding region in susceptibility for ovarian failure

BACKGROUND

Elevation of FSH is frequently a consequence of impaired ovarian follicle growth. Down-regulation of the FSH levels by inhibins is mediated through its receptor betaglycan in the gonadotrophs. Understanding of germline status of the betaglycan gene (TGFBR3) is essential for ovarian failure pathophysiology.

METHODS

Sequence analysis was performed for the coding region of TGFBR3 gene in a cohort of 196 ovarian failure cases that include 133 premature ovarian failure (POF) cases, 63 primary amenorrhoea (PA) cases compared with 200 controls.

RESULTS

Forty-six variants including six novel exonic variants and 16 novel intronic variants were revealed. Two variants were missense: (i) p.Iso184Val in a control and (ii) p.Pro775Ser in a POF case. Genotypic distribution of three variants (c.382-81C>T, c.382-77T>C and c.1200G>A) was significantly different in the patients as compared with the controls. Five variants c.382-81C>T, c.382-77T>C, c.566-216G>A, c.1200G>A and c.2022T>C were chosen for haplotyping. The CCAAT haplotype was significantly higher in the patient population as compared with the controls (P = 0.00007).

CONCLUSION

This study establishes the first mutational report of the TGFBR3 gene in correlation with ovarian failure. Significant diversity of genotype distribution and haplotype analysis suggested susceptibility of the TGFBR3 gene for ovarian failure aetiology.

Loss of constitutive activity of the growth hormone secretagogue receptor in familial short stature

The growth hormone (GH) secretagogue receptor (GHSR) was cloned as the target of a family of synthetic molecules endowed with GH release properties. As shown recently through in vitro means, this receptor displays a constitutive activity whose clinical relevance is unknown. Although pharmacological studies have demonstrated that its endogenous ligand--ghrelin--stimulates, through the GHSR, GH secretion and appetite, the physiological importance of the GHSR-dependent pathways remains an open question that gives rise to much controversy. We report the identification of a GHSR missense mutation that segregates with short stature within 2 unrelated families. This mutation, which results in decreased cell-surface expression of the receptor, selectively impairs the constitutive activity of the GHSR, while preserving its ability to respond to ghrelin. This first description, to our knowledge, of a functionally significant GHSR mutation, which unveils the critical importance of the GHSR-associated constitutive activity, discloses an unusual pathogenic mechanism of growth failure in humans.

Premature ovarian failure

Premature ovarian failure (POF) is a primary ovarian defect characterized by absent menarche (primary amenorrhea) or premature depletion of ovarian follicles before the age of 40 years (secondary amenorrhea). It is a heterogeneous disorder affecting approximately 1% of women <40 years, 1:10,000 women by age 20 and 1:1,000 women by age 30. The most severe forms present with absent pubertal development and primary amenorrhea (50% of these cases due to ovarian dysgenesis), whereas forms with post-pubertal onset are characterized by disappearance of menstrual cycles (secondary amenorrhea) associated with premature follicular depletion. As in the case of physiological menopause, POF presents by typical manifestations of climacterium: infertility associated with palpitations, heat intolerance, flushes, anxiety, depression, fatigue. POF is biochemically characterized by low levels of gonadal hormones (estrogens and inhibins) and high levels of gonadotropins (LH and FSH) (hypergonadotropic amenorrhea). Beyond infertility, hormone defects may cause severe neurological, metabolic or cardiovascular consequences and lead to the early onset of osteoporosis. Heterogeneity of POF is also reflected by the variety of possible causes, including autoimmunity, toxics, drugs, as well as genetic defects. POF has a strong genetic component. X chromosome abnormalities (e.g. Turner syndrome) represent the major cause of primary amenorrhea associated with ovarian dysgenesis. Despite the description of several candidate genes, the cause of POF remains undetermined in the vast majority of the cases. Management includes substitution of the hormone defect by estrogen/progestin preparations. The only solution presently available for the fertility defect in women with absent follicular reserve is ovum donation.

Expression of growth differentiation factor 9 in the oocytes is essential for the development of primordial follicles in the hamster ovary

Postnatal growth differentiation factor 9 (GDF-9) expression in the hamster oocytes precedes the formation of primordial follicles. We examined the functional significance of GDF-9 in primordial folliculogenesis in the hamster ovary using RNA interference knockdown of GDF-9 mRNA and protein expression. Fifteen-day-old fetal ovaries were cultured for 9 d with or without 1 ng FSH, 1 microl Metafectane, 100 nM control nontargeting small interfering RNA (siRNA), GDF-9 siRNA, or GDF-9 siRNA + FSH, and the development of primordial follicles examined. The efficiency of siRNA transfecting ovarian cells in the organ culture was tested by culturing ovaries with siGlo, a nontargeting control siRNA labeled with Cy3. More than 90% of cells in the ovary were siGlo positive, and neither the Metafectane nor the siRNA-induced cellular apoptosis. Control siRNA did not affect the basal levels of GDF-9 mRNA, but GDF-9 siRNA slightly but significantly reduced the level. FSH markedly up-regulated the levels of GDF-9 mRNA and protein, and the effect was completely suppressed by GDF-9 siRNA. However, GDF-9 siRNA did not affect the levels of bone morphogenetic protein receptor IA or beta-actin mRNA. GDF-9 siRNA alone also reduced GDF-9 protein expression. Concurrent with GDF-9 expression, FSH significantly augmented primordial follicle formation, but the effect was abolished by GDF-9 siRNA. These results suggest that endogenous GDF-9 plays an important role in somatic cell differentiation and the formation of primordial follicles. Furthermore, FSH, by virtue of regulating GDF-9 expression, modulates oocyte regulation of primordial follicles formation.

Allosteric activation of the follicle-stimulating hormone (FSH) receptor by selective, nonpeptide agonists

The pituitary glycoprotein hormones, luteinizing hormone and follicle-stimulating hormone (FSH), act through their cognate receptors to initiate a series of coordinated physiological events that results in germ cell maturation. Given the importance of FSH in regulating folliculogenesis and fertility, the development of FSH mimetics has been sought to treat infertility. Currently, purified and recombinant human FSH are the only FSH receptor (FSH-R) agonists available for infertility treatment. By screening unbiased combinatorial chemistry libraries, using a cAMP-responsive luciferase reporter assay, we discovered thiazolidinone agonists (EC50's = 20 microm) of the human FSH-R. Subsequent analog library screening and parallel synthesis optimization resulted in the identification of a potent agonist (EC50 = 2 nm) with full efficacy compared with FSH that was FSH-R-selective and -dependent. The compound mediated progesterone production in Y1 cells transfected with the human FSH-R (EC50 = 980 nm) and estradiol production from primary rat ovarian granulosa cells (EC50 = 10.5 nm). This and related compounds did not compete with FSH for binding to the FSH-R. Use of human FSH/thyroid-stimulating hormone (TSH) receptor chimeras suggested a novel mechanism for receptor activation through a binding site independent of the natural hormone binding site. This study is the first report of a high affinity small molecule agonist that activates a glycoprotein hormone receptor through an allosteric mechanism. The small molecule FSH receptor agonists described here could lead to an oral alternative to the current parenteral FSH treatments used clinically to induce ovarian stimulation for both in vivo and in vitro fertilization therapy.

Missense mutations in the BMP15 gene are associated with ovarian failure

Premature ovarian failure (POF) is an unexplained amenorrhoea (>6 months) with raised levels of gonadotropins (FSH>40 U/L) occurring before the age of 40 years. Recent studies have elucidated the role of oocyte derived growth factors (BMP15 and GDF9) in maintenance of folliculogenesis, granulosa cell (GC) proliferation and overall fertility. Our recently published work showed presence of two rare missense variants in the GDF9 gene associated with ovarian failure (Dixit et al. 2005, Menopause 12:749-754). The present case-control study has been structured to establish the role of BMP15 germline status associated with ovarian failure. Sequence analysis of the coding region of the BMP15 gene was carried out in a cohort of women with POF (n=133), primary amenorrhoea (n=60), and secondary amenorrhoea (n=9) compared with control females (n=197). This study revealed a total of 18 germline variants in the coding region of BMP15 gene, including 16 novel variants. These novel variants include one intronic variant, one 3' flanking variant, one silent variant, and 13 missense variants. Eleven missense variants were present only in cases with complete absence in the control females. The remaining two missense variants viz. c.308A>G (p.Asn103Ser) and c.788_789insTCT (p.Leu263_Arg264insLeu) were present both in the cases and in the controls. The c.788_789insTCT variant was significantly higher in primary amenorrhoea cases than in the controls (Fisher's exact test, P=0.034). Three frequent variants c.-9C>G, c.308A>G, and c.852C>T were chosen for haplotyping. The haplotype G-G-C was found to be significantly associated with ovarian failure (P=0.0075). In a nutshell, the BMP15 gene is highly associated with etiology of ovarian failure.

Idiopathic Premature Ovarian Failure in 63 Young Women

BACKGROUND

Premature ovarian failure (POF) in adolescents is defined as primary or secondary amenorrhea associated with high follicle-stimulating hormone (FSH) levels. In normal 46,XX patients, its etiology is most often unknown. We have evaluated the clinical, hormonal and ovarian phenotypes in patients with a normal karyotype who were diagnosed with POF before the age of 18.

METHODS

Sixty-three patients were included in this retrospective study.

RESULTS

The mean patient age was 20.4 years. The patients presented with three clinical patterns: lack of pubertal development (n = 23), primary amenorrhea with interrupted puberty (n = 18), and secondary amenorrhea with normal puberty (n = 22). Ten patients had a familial history of POF and 6 presented with hypothyroidism. The FSH, estradiol and inhibin B levels were not statistically different in the three clinical groups. Fifty percent of the patients presented small ovaries (length <2 cm) at ultrasonography. The presence of follicles was found at histology in only 7 of the 27 patients who underwent an ovarian biopsy.

CONCLUSION

46,XX patients presenting with early POF rarely presented a specific, identifiable disorder. We discuss the clinical management and different diagnosis strategies to improve our current knowledge of this syndrome.

Chromosomal rearrangements in Xq and premature ovarian failure: mapping of 25 new cases and review of the literature

BACKGROUND

Chromosomal rearrangements in Xq are frequently associated with premature ovarian failure (POF) and have defined a POF 'critical region'. Search for genes responsible for the disorder has been elusive.

METHODS

We report mapping of novel breakpoints of X;autosome-balanced translocations and interstitial deletions and a review of published X chromosome rearrangements.

RESULTS

All the novel POF-associated rearrangements were mapped outside and often very distant from genes. The majority mapped to a gene-poor region in Xq21. In the same region, deletions were reported in women who apparently did not have problems conceiving. Expression analysis of genes flanking breakpoints clustered in a 2-Mb region of Xq21 failed to demonstrate ovary-specific genes.

CONCLUSIONS

Our results excluded most of the possible explanations for the POF phenotype and suggested that POF should be ascribed to a position effect of the breakpoints on flanking genes. We also showed that while the X breakpoint may affect X-linked genes in the distal part of Xq, from Xq23 to Xq28, interruption of the critical region in Xq21 could be explained by a position effect of the Xq critical region on genes flanking the autosomal breakpoints.

Screening of the galactose-1-phosphate uridyltransferase gene in Indian women with ovarian failure

The present study was aimed at mutational screening of the gene coding for galactose-1-phosphate uridyltransferase in females with premature ovarian failure within an Indian population. A case-control-based study approach was used. It included females with premature ovarian failure (n = 108), primary amenorrhoea (n = 37) and secondary amenorrhoea (n = 9), and a control group of 136 women with a normal ovarian pattern. Gene sequencing analysis for the presence of mutations in the promoter and the coding regions of GALT has shown the absence of any mutation. A hexanucleotide deletion was found in the third intronic region of GALT in both cases and controls. These data support the hypothesis that there is no significant association between GALT mutations and ovarian failure, and hence the present authors conclude that there is no relationship between ovarian failure and GALT polymorphisms in Indian women.

Pharmacogenetics in ovarian stimulation - current concepts and future options

Tailoring ovarian stimulation to the individual patient can be challenging because the ovarian response varies substantially between patients. Pharmacogenetics has emerged as a new area of research to improve the balance between desired and undesired actions of drugs, based upon the genetic predisposition of the individual patient. Clinical studies have demonstrated that the p.N680S polymorphism of the FSH-receptor gene determines the ovarian response to FSH stimulation in patients undergoing IVF. In homozygous Ser(680)/Ser(680) type women, the FSH receptor appears to be more resistant to FSH action even in normal menstrual cycles. Therefore, genotyping of patients scheduled for ovarian stimulation could be an attractive tool to individualize FSH dosing according to genetic differences in ovarian sensitivity. More clinical studies are warranted to investigate the usefulness of genotyping for the p.N680S polymorphism as a routine diagnostic test before ovarian stimulation.

Variations of the Amnionless gene in recurrent spontaneous abortions

Recurrent spontaneous abortions (RSA) are estimated to affect 0.5-1% of couples trying to have a child. The causes of RSA are unknown in the majority of cases. This study aimed to determine whether homozygous mutations in the AMN gene in a fetus cause spontaneous abortions in humans, as they are known to cause spontaneous abortions in mice. The study was conducted by screening 40 couples and 5 women with three or more unexplained spontaneous abortions for heterozygous mutations in the AMN gene using denaturing high-performance liquid chromatography. Altogether, 3 exonic and 11 intronic sequence variations were found. There were no significant differences in the frequencies of the variations between the patients and a control group. One of the exonic variations was non-synonymous, and three of the variations may affect gene splicing. None of the putative phenotype-affecting variations were found in both partners in any couple. These results indicate that RSA in the couples studied cannot be explained by homozygous AMN mutations in the fetus. However, two couples had different, potentially deleterious variations in both partners. If these variations have a phenotypic effect, the RSA experienced by these couples may be caused by mutations in the AMN gene. In addition, birthplaces of the patients' ancestors revealed some clustering, suggesting that some patients may carry a founder mutation in another gene which may contribute to RSA.

Controversial role of inhibin α-subunit gene in the aetiology of premature ovarian failure

BACKGROUND

Premature ovarian failure (POF) is characterized by hypergonadotropic amenorrhoea before the age of 40. Inhibin alpha-subunit (INHalpha) gene is proposed as a candidate gene due to its role in negative feedback control of FSH.

METHODS

Polymorphism -16C>T of INHalpha gene was studied in 61 POF patients and 82 controls above 40 years old (C > 40). Substitution 769G>A was studied in 59 POF patients, 76 C > 40 and 73 controls below 40 years old (C < 40).

RESULTS

No significant difference in risk of POF development for -16T allele was found when comparing idiopathic POF (I-POF) with C > 40 (Odds ratio = 1.46; 95% confidence interval = 0.63-3.19). Implication of -16C>T polymorphism in serum inhibin levels was analysed in 46 controls, and no significant differences (P > 0.05) were found between CC and CT + TT genotype groups when comparing either mid-follicular phase Pro-alphaC and inhibin B values or mid-luteal phase Pro-alphaC and inhibin A values. Heterozygosity for substitution 769G>A was found in 1 of 59 POF woman, 2 of 76 C > 40 and 6 of 73 C < 40. Presence of this substitution in a relevant number of control subjects is herein described for the first time.

CONCLUSION

Our results indicate that -16C>T and 769G>A variants in INHalpha gene may not be associated to POF disease.

INHA promoter polymorphisms are associated with premature ovarian failure

Inhibin is an important glycoprotein that is involved in folliculogenesis. INHA, the gene encoding the inhibin alpha subunit, was recently proposed as a candidate for premature ovarian failure (POF), a syndrome that leads to the cessation of ovarian function under the age of 40 years. 70 POF patients and 70 controls were screened for the previously identified INHA -16C>T transition mutation. The T allele was found in 31/70 (44.3%) of controls, but only 18/70 (25.7%) of POF patients. This result indicates that the T allele is significantly underrepresented in the POF patient population (Fisher's exact test, two-tail: P = 0.033). Sequence analysis of the INHA promoter in 50 POF patients and 50 controls identified a highly polymorphic imperfect TG repeat at approximately -300 bp, that consisted of four common haplotypes (A, B, C and D). The -16T allele is linked to the shortest repeat haplotype (haplotype C). Despite the association between haplotype C and POF, no significant difference was found between the promoter activity of a luciferase reporter construct containing haplotype C, and most of the other haplotypes tested. Interestingly, haplotype B failed to show any promoter activity. We conclude that the inheritance of specific INHA promoter haplotypes predispose to the development of premature ovarian failure.

PKA Implicated in the Phosphorylation of Cx43 Induced by Stimulation with FSH in Rat Granulosa Cells

Connexin 43 (Cx43)-mediated gap junctional communication in granulosa cells is crucial for germ line development and postnatal folliculogenesis. We previously showed that follicle-stimulating hormone (FSH) promoted phosphorylation of Cx43 in rat primary granulosa cells. We further identified Ser365, Ser368, Ser369, and Ser373 in the carboxy-terminal tail as the major sites of phosphorylation by FSH, and found that the phosphorylation of these residues was essential for channel activity. In this study, we investigated the protein kinase(s) responsible for FSH-induced phosphorylation. H89, a cyclic AMP-dependent protein kinase (PKA) inhibitor, inhibited FSH-induced phosphorylation both in vivo and in vitro, whereas PD98059, a mitogen-activated protein kinase kinase (MEK) inhibitor, had little effect on the phosphorylation level. Ca2+-dependent protein kinase (PKC) appeared to negatively regulate phosphorylation. Phosphopeptide mapping with or without H89 treatment indicated that PKA could be responsible for phosphorylation of the four serine residues. In addition, the purified catalytic subunit of PKA could phosphorylate the recombinant C-terminal region of Cx43, but not the variant in which all four serine residues were substituted with alanine. These results suggest that FSH positively regulates Cx43-mediated channel formation and activity through phosphorylation of specific sites by PKA.

FSH receptor gene polymorphisms in fertile and infertile Italian men

In women, single nucleotide polymorphisms (SNP) of the FSH receptor (FSHR) gene influence FSH concentrations and the sensitivity of the FSHR to FSH in vivo. In contrast, the significance of FSHR R gene SNP in the male is poorly understood. To this aim, the possible role of three FSHR SNP was evaluated in male infertility. SNP in exon 10 (codon 307 and 680) and in the core promoter region (at position -29) of the FSHR gene were analysed by polymerase chain reaction-restriction fragment length polymorphism technique in 150 men representative of the general population, 107 proven fathers, 92 normozoospermic controls, and 215 infertile patients classified according to sperm parameters (38 azoospermia, 53 severe oligozoospermia, 48 moderate oligozoospermia, and 76 slight oligozoospermia). Reproductive hormones were measured in infertile males and normozoospermic controls. No significant difference was found in allelic variants frequency and genotype distribution between each category of subjects when analysing the FSHR exon 10 SNP alone and in combination with the SNP at position -29. Serum FSH concentrations and other andrological parameters did not differ between subjects with different genotype within each group. The data showed that in the Italian population, FSHR genotypes have no influence on FSH concentrations both in normal and infertile males and do not associate with spermatogenetic impairment.

What have we learned about gonadotropin function from gonadotropin subunit and receptor knockout mice?

A number of biochemical and physiological studies elucidated the roles of pituitary and placental glycoprotein hormones. Advances in the past two decades in manipulating the mouse genome by random or site-specific mutagenesis have heralded a new dimension to our understanding of the biology of gonadotropins. It is now possible to model many human reproductive disorders involving gonadotropins/gonadotropin-signaling in the mouse. Mutant mice selectively lacking either FSH or LH or their cognate receptors have been generated. The gonadotropin ligand and the corresponding receptor knockout mice mostly phenocopy each other. Analyses with these genetic models confirmed earlier physiological studies; in addition they also revealed novel roles for gonadotropins previously unrecognized. While FSH action seems dispensable for male but not female fertility, absence of LH causes infertility in both the sexes. While Sertoli cell number and germ cell carrying capacity of the Sertoli cells in compromised in FSH mutants, both somatic and germ cell lineages are affected in the LH mutants resulting in complete male infertility. FSH mutant females demonstrate a preantral stage block in folliculogenesis and FSH alone is not sufficient to promote full folliculogenesis in the absence of LH. Pre-ovulatory stage follicles do not form and most of the follicles undergo apoptosis in the absence of LH. Many extra-gonadal phenotypes have been described for the receptor knockout mice and whether these bear any resemblances to those in patients with similar inactivating mutations in the receptors for FSH and LH remains an open question. Thus the in vivo models will continue to have a significant impact in understanding gonadotropin physiology and pathophysiology and serve as novel genetic tools to study signaling mechanisms in the gonads.

An update: spontaneous premature ovarian failure is not an early menopause

OBJECTIVE

To update clinicians regarding the management of women with spontaneous premature ovarian failure (POF).

DESIGN

Literature review and consensus building among three clinicians with experience in caring for women with spontaneous POF.

CONCLUSION(S)

Clearly the ovarian "failure" in this disorder is not permanent in all women. Approximately 5%-10% may conceive spontaneously and unexpectedly after the diagnosis. An integrated approach to management is best, and there is a need to first address physical and mental health issues before addressing plans for family building. Women with spontaneous POF are at increased risk of adrenal insufficiency, which should be detected and managed appropriately, especially before proceeding to ovum or embryo donation procedures. Young women with POF experience pathologically low serum E2 levels at least intermittently. Despite the absence of controlled evidence for this specific population, physiologic replacement of ovarian steroid hormones seems rational until the age of normal menopause. The disorder may be associated with other conditions that require evaluation and management, including hypothyroidism, dry eye syndrome, abnormal karyotype, or a premutation of the FMR1 gene. Finally, clinicians need to be sensitive to the emotional aspects of this disorder when delivering the diagnosis and during subsequent management.

Aberrant expression of PDGF ligands and receptors in the tumor prone ovary of follitropin receptor knockout (FORKO) mouse

Although PDGF family members play a vital role in cell proliferation, motility and chemotaxis via activation of structurally similar alpha- and beta-receptors, little is known of their function in ovarian regulation and induction of tumorigenesis. Microarray analyses of ovaries from young follitropin receptor knockout (FORKO) mice that are prone to late ovarian tumors upon aging have revealed significant imbalances in PDGF ligands and receptors. We hypothesized that FSH/FSH-R signaling may exert effects partly by regulation of PDGF the family. To further understand their implications for ovarian tumorigenesis, we studied FORKO ovaries and hormonal regulation of the PDGF family members in normal mice, by using RT-PCR, Q-PCR, immunohistochemistry and western blotting. While PDGF-C and PDGFR-alpha increased, PDGFR-beta mRNA and protein decreased significantly in absence of FSH-R signaling. In the normal ovary, PDGFR-alpha was not affected by gonadotropin (eCG) stimulation but PDGF-C and PDGFR-beta decreased. Administration of estradiol decreased PDGF and their receptors. To further probe the differential regulation of PDGF family members by eCG and estradiol, we co-administered eCG with estrogen antagonist, ICI 182780. Increase in PDGFR-alpha in the absence of estradiol suggests direct effects of FSH signaling. During the estrous cycle in mice PDGF-C, PDGF-D and PDGFR-alpha mRNA levels were higher at the proestrous. By IHC, we report for the first time the localization of PDGF-C, PDGFR-alpha and PDGFR-beta protein in mouse ovarian compartments including the surface epithelium that is also altered in mutants. Immunostaining of PDGFRs increased as the follicle developed to preantral stage and declined thereafter. Thus, FSH modulates PDGF family members, partly via E2, suggesting that loss of FSH-R signaling causes an imbalance of PDGF family members predisposing the abnormal ovarian follicular environment for inducing tumorigenesis in aging FORKO mice.

Variants in Deleted in AZoospermia-Like (DAZL) are correlated with reproductive parameters in men and women

Qualitative and quantitative defects in human germ cell production that result in infertility are common and determined at least in part by genetic factors [Matzuk and Lamb, Nat Cell Biol 4(Suppl):s41-s49, 2002]. Yet, very few genes that are associated with germ cell defects in humans have been identified. In this study, we examined whether variants of the Deleted in AZoospermia-Like (DAZL) gene are associated with measures of germ cell production in three distinct populations of men and women. We identified 95 sequence variants in DAZL and further analyzed twelve single nucleotide polymorphisms (SNPs) that were present across ethnicities. We found that seven of the twelve SNPs were associated with at least one of the parameters studied (age at premature ovarian failure or menopause, total sperm count, or total motile sperm count). Surprisingly, many alleles exhibited opposing effects in men and women, which may be a result of different genetic requirements in male and female germ cells. Single SNP and haplotype analysis suggested that SNPs in the DAZL gene may act jointly to affect common reproductive characteristics in the human population.

Mutational screening of the coding region of growth differentiation factor 9 gene in Indian women with ovarian failure

OBJECTIVE

To establish the risk associated with mutations in the coding region of GDF9 gene in Indian women with ovarian failure.

DESIGN

This case-control study was designed for mutational analysis of the GDF9 coding region in a cohort of women with premature ovarian failure (n = 127), primary amenorrhea (n = 58), and secondary amenorrhea (n = 10) compared with controls (n = 220).

RESULTS

This case-control study revealed eight mutations in the GDF9 gene, including five novel mutations: c.1-8C>T, c.199A>C (p.Lys67Glu), c. 205C>T, c.646G>A (p.Val216Mat), and c.1353C>T, and three documented mutations: c.398-39C>G, c.447C>T, and c.546G>A. Missense mutation c.199A>C was present in 4 of 127 premature ovarian failure (POF) cases and 1 of 10 secondary amenorrhea cases. The c.646G>A mutation was present in two POF cases. Both missense mutations were absent in controls. Genotype distribution of c.447C>T was significantly different in POF cases than controls (chi(2) = 5.93, P = 0.05). We chose two frequent single-nucleotide polymorphisms (c.398-39C>G, c.447C>T) for haplotyping and found that the C-T haplotype was significantly higher in patients (P = 0.03), whereas the C-C haplotype was representative of the control group.

CONCLUSIONS

We report two rare missense mutations, c.199A>C and c.646G>A, which are associated with ovarian failure. The presence of the c.447>T mutation might indicate a higher risk for POF. Haplotype C-T was significantly associated with ovarian failure, whereas the C-C haplotype was representative of the control group.