Premature ovarian failure

Intermittent ovarian and thyroid failure and spontaneous twin pregnancy

Intermittent failure of two endocrine systems is unusual and presents diagnostic and management challenges. We report a case of a young woman with intermittent thyroid and ovarian failure who had spontaneous twin gestation four years after the diagnosis of premature ovarian failure was made. This case demonstrates coincidental biochemical and clinical thyroid and ovarian failure both of which spontaneously resolved with no treatment, although subsequently irreversible hypothyroidism ensued after the initial recovery. Elevated gonadotrophins with a menopausal pattern on more than one occasion, in an amenorrhoeic patient with menopausal symptoms, usually indicates permanent ovarian failure. This case demonstrates that this may not be true and while this is probably a rare occurrence, clinicians need to be aware of this possibility. It also re-emphasizes the need to consider the clinical picture when interpreting biochemical results.

Blepharophimosis-ptosis-epicanthus inversus syndrome in a girl with chromosome translocation t(2;3)(q33;q23)

We report on a young female patient with the clinical features of blepharophimosis-ptosis-epicanthus inversus syndrome (BPES, OMIM 110100) and a balanced chromosome translocation 46, XX, t(2;3)(q33;q23)dn.BPES is a rare autosomal dominant congenital disorder characterized by the eponymous oculo-facial features that are, in female patients, associated either with (type 1 BPES) or without (type 2 BPES) premature ovarian failure. Both types of BPES are caused by heterozygous mutations in the FOXL2 gene, which is located in chromosome band 3q23. Chromosome aberrations such as balanced rearrangements have only rarely been observed in BPES patients but can provide valuable information about regulatory regions of FOXL2. The translocation in this patient broadens our knowledge of pathogenic mechanisms in BPES and highlights the importance of conventional cytogenetic investigations in patients with negative results of FOXL2 mutation screening as a prerequisite for optimal management and genetic counseling.

Maternal exposure to polycyclic aromatic hydrocarbons diminishes murine ovarian reserve via induction of Harakiri

Maternal smoking during pregnancy is associated with a variety of adverse neonatal outcomes including altered reproductive performance. Herein we provide molecular evidence for a pathway involved in the elimination of the female germline due to prepregnancy and/or lactational exposure to polycyclic aromatic hydrocarbons (PAHs), environmental toxicants found in cigarette smoke. We show that ovaries of offspring born to mice exposed to PAHs contained only a third of the ovarian follicle pool compared with offspring of unexposed female mice. Activation of the cell death pathway in immature follicles of exposed females was mediated by the aryl hydrocarbon receptor (Ahr), as ovarian reserve was fully rescued by maternal cotreatment with the Ahr antagonist, resveratrol, or by inactivation of the Ahr gene. Furthermore, in response to PAHs, Ahr-mediated activation of the harakiri, BCL2 interacting protein (contains only BH3 domain), was necessary for execution of cell death. This pathway appeared to be conserved between mouse and human, as xenotransplanted human ovarian cortex exposed to PAHs responded by activation of the identical cell death cascade. Our data indicate that maternal exposure to PAHs prior to pregnancy and/or during lactation compromises ovarian reserve of female offspring, raising the concern about the transgenerational impact of maternal smoking on ovarian function in the human.

Non-chromosomal, non-iatrogenic premature ovarian failure in an adolescent population: a case series

STUDY OBJECTIVE

To review a cohort of patients with non-chromosomal, non-iatrogenic premature ovarian failure (POF) presenting to the Gynaecology Clinic of the Royal Children's Hospital, Melbourne.

DESIGN

Case series

SETTING

The Department of Gynaecology, Royal Children's Hospital, Melbourne, Victoria, Australia.

PARTICIPANTS

Adolescent patients with non-chromosomal, non-iatrogenic premature ovarian failure

RESULTS

Seventeen patients with non-chromosomal, non-iatrogenic POF were identified between 1990 and 2006. The average age at the time of diagnosis was 16.1 years. 58.8% (10/17) presented with primary amenorrhea, 23.5% (4/17) with secondary amenorrhea and 17.6% (3/17) with oligomenorrhea. 41.1% (7/17) were positive for anti-nucleic acid antibodies and one patient had antithyroid antibodies. Two sets of sisters were identified.

CONCLUSION

Non-chromosomal, non-iatrogenic POF in an adolescent population is poorly characterized and its incidence unknown. It most commonly presents as primary amenorrhea, but may also present as a disturbance in a previously established menstrual cycle. Like adult onset POF, there appears to be an association with autoimmune conditions although, in our population, overt autoimmune conditions were rare. The occurrence of POF in two sets of sisters raises the possibility of a genetic basis of the condition being more significant in the younger age group, and provides an interesting cohort for further studies in the area.

The mutations and potential targets of the forkhead transcription factor FOXL2

Mutations of FOXL2, a gene encoding a forkhead transcription factor, have been shown to cause the blepharophimosis-ptosis-epicanthus inversus syndrome (BPES). This genetic disorder is characterized by eyelid and mild craniofacial abnormalities that can appear associated with premature ovarian failure. FOXL2 is one of the earliest ovarian markers and it offers, along with its targets, an excellent model to study ovarian development and function in normal and pathological conditions. In this review we summarize recent data concerning FOXL2, its mutations and its potential targets. Indeed, many mutations have been described in the coding sequence of FOXL2. Among them, polyalanine expansions and premature nonsense mutations have been shown to induce protein aggregation. In the context of the ovary, FOXL2 has been suggested to be involved in the regulation of cholesterol and steroid metabolism, apoptosis, reactive oxygen species detoxification and inflammation processes. The elucidation of the impact of FOXL2 mutations on its function will allow a better understanding of the pathogenic mechanisms underlying the BPES phenotype.

Recent advances in the study of genes involved in non-syndromic premature ovarian failure

Premature ovarian failure (POF) is a common pathology leading to infertility affecting about 1% of women under 40 years old. In POF patients, the ovarian dysfunction is characterized by the lack of the ovarian response to close a negative feedback loop on the synthesis of pituitary gonadotropins. Although the majority of cases are considered as idiopathic, diverse aetiologies have been associated, including genetic factors. Up to now, the potential genetic causes of non-syndromic POF have been established mainly by genetic linkage analysis of familial cases or by the screening of mutations in candidate genes based on animal models. Here, we review recent advances in the study of candidate genes.

BMP15 mutations in XX gonadal dysgenesis and premature ovarian failure

OBJECTIVE

Premature ovarian failure (POF) is a heterogeneous group of diseases with amenorrhea before the age of 40 years and elevated gonadotropins. Recently, heterozygous mutations in the X-linked gene encoding bone morphogenetic protein-15 (BMP15) have been identified as a possible cause of ovarian failure.

STUDY DESIGN

Molecular analysis of BMP15, growth differentiation factor-9 (GDF9), and follicle-stimulating hormone receptor (FSHR) in patients with ovarian failure.

RESULTS

We can show that a BMP15 alteration, previously described as a mutation, is instead a polymorphism. A digenic inheritance of POF including BMP15 and FSHR is unlikely. Mutations in GDF9 could not be detected.

CONCLUSION

Caution is recommended in the interpretation of BMP15 mutations in the context of POF.

Premature ovarian failure in suspected Whipple's disease

INTRODUCTION

Whipple's disease is a relapsing systemic infectious disease probably caused by the Gram-positive bacillus Tropheryma whippelii. The diagnosis can be established based on the characteristic histopathological features found in the affected organ (foamy macrophages with a coarsely granular cytoplasm, which stains with PAS, and by means of polymerase chain reaction (PCR) technology).

CASE REPORT

We report a case of a 23-year-old woman affected by suspected Whipple's disease. She presented encephalopathy and neuropathy with inveterate hyperpyrexia and alteration of the hypothalamic-pituitary-ovary axe. She was amenorrheic because of an hypergonadotropic hypogonadism.

DISCUSSION

This hypogonadism is possibly due to follicular depletion caused by inveterate hyperpyrexia or T. whipplii localization.

Premature ovarian failure in a patient with a complex chromosome rearrangement involving the critical region Xq24, characterized by analysis using fluorescence in situ hybridization by chromosome microdissection

OBJECTIVE

To characterize a complex chromosome rearrangement previously detected by G-banding in peripheral blood lymphocytes as 46,X, inv(X)(p11;q2?), inv(4)(q?),ins(8)(q?) in a patient with primary amenorrhea.

DESIGN

Case report.

SETTING

University faculty of medicine and hospital.

PATIENT(S)

A 16-year-old girl with primary amenorrhea.

INTERVENTION(S)

Microdissection of chromosomes labeled by fluorescence in situ hybridization and by reverse painting.

MAIN OUTCOME MEASURE(S)

Use of commercial whole-chromosome painting probes for the detection of the aberrant chromosomes 4, 8, and X. Fluorescence probes of the isolated derivative chromosomes are self-generated.

RESULT(S)

The use of whole-chromosome painting probes allowed reliable identification of all chromosomes involved in the complex chromosome rearrangements. The DNA of those chromosomes was amplified and fluorescence labeled by polymerase chain reaction using degenerated oligonucleotide primers. These probes revealed breakpoints of the complex chromosome rearrangement by hybridization on normal and original chromosomes in 4q31.1, 8q24.1, Xp22.1, Xp11.4, and Xq24.

CONCLUSION(S)

We report on an Indian patient who has premature ovarian failure with primary amenorrhea as well as a hormone level increased for LH and FSH but decreased for TSH. She has a balanced complex translocation with three breakpoints in the X chromosome that were located by fluorescence in situ hybridization by chromosome microdissection, but no breakpoints localized in the critical regions for premature ovarian failure on the X chromosome. The breakpoint in Xq24 may be associated with the amenorrhea.

Detection of antizona pellucida antibodies in the sera from premature ovarian failure patients by a highly specific test

OBJECTIVE

To develop a highly specific test for the detection of antizona pellucida (ZP) antibodies in the sera from premature ovarian failure (POF) patients.

DESIGN

Laboratory study.

SETTING

University hospital.

PATIENT(S)

Twenty-seven idiopathic POF patients, 30 control women, and 30 healthy males.

INTERVENTION(S)

Anti-ZP antibodies were detected by the microdot assay using a very small amount of human ZP or porcine ZP. The effect of anti-ZP antibodies on sperm-ZP binding was examined by hemizona assay.

MAIN OUTCOME MEASURE(S)

Results from the microdot assay and hemizona assay.

RESULT(S)

By the microdot assay using human ZP, the sera from POF patients reacted significantly stronger than those of control women and healthy males. However, no obvious difference could be found by the same assay using porcine ZP among these three groups. Anti-ZP antibodies against sera from some POF patients showed significant blocking effects on sperm-ZP binding assessed by hemizona assay. Anti-ZP antibodies were detected in 7 of 27 POF patients, while none were detected in control women and healthy males.

CONCLUSION(S)

Some idiopathic POF patients have anti-ZP antibodies in their sera, which were detected with high specificity by a newly developed microdot assay using a very small amount of human ZP.

Gene analysis in patients with premature ovarian failure or gonadal dysgenesis: A preliminary study

OBJECTIVE

The aim of this study was to evaluate the presence of mutations in the coding region of the QM gene and fragile X in patients with premature ovarian failure and gonadal dysgenesis.

METHODS

After approval by the local Ethics Committee, blood samples, in EDTA, of 100 normally ovulating women, 23 with premature ovarian failure (POF) and 14 with gonadal dysgenesis 46XX, aged less than 40 years, were screened for mutation in the QM gene coding region. All patients with POF have 46, XX karyotype and serum levels of follicle-stimulating hormone (FSH) over 30 mIU/mL. In addition, all samples from patients with premature ovarian failure underwent analysis for fragile X.

RESULTS

The QM gene located at a hotspot region (Xq28) showed five points of mutations in a patient with premature ovarian failure. Four of them were able to change the amino acid sequence of the protein. None of our patients were diagnosed as having pre or mutant X fragile syndrome.

CONCLUSION

Our study suggests that Xq28 (QM gene) may be involved in ovary failure. However, further studies are needed to confirm this hypothesis.

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.

A new mutation in TP63 is associated with age-related pathology

Increases in the number of allelic malformation syndromes have led to their classification according to their pathogenesis rather than their clinical specific phenotype. TP63 (also known as TP73L) mutations have been identified in several such syndromes characterized by autosomal dominant transmission and various combinations of ectodermal dysplasia, limb malformations and orofacial clefting. TP63 has not yet been implicated in early aging phenotype in humans, even though p63 activates a program of cellular senescence and p63-compromised mice display features of accelerated aging. We report on a family with four affected adult females presenting with Rapp-Hodgkin syndrome (RHS), an autosomal dominant clinical entity that associates anhidrotic ectodermal dysplasia with cleft lip and palate. Features between RHS and EEC syndrome (ectrodactyly, ectodermal dysplasia and cleft lip/palate) have led to the recent identification of mutations in the TP63 gene, located on 3q27, in this condition. Our patients present typical clinical features of RHS, but also ophthalmic anomalies such as corneal dystrophy and premature menopause (around 30 years). The latter findings have never been reported in this condition, and could be secondary to a new TP63 deletion that has been identified in this family.

Androgen receptor function in folliculogenesis and its clinical implication in premature ovarian failure

The action of estrogen in the female reproductive organs is well known in terms of the expression pattern and gene regulation of the estrogen receptor (ER). The significance of ERs in female reproduction is undisputed. The role of the androgen receptor (AR) is less clear. Clinical hyperandrogenism, a typical feature of polycystic ovary syndrome (PCOS), highlights pathological androgen production by the ovary. By contrast, the physiological impact of androgen action in female reproductive organs remains elusive. Androgens affect folliculogenesis in a variety of experimental approaches and ARs are expressed in developing follicles. Recent observations have discovered that inactivation of ARs in female mice results in premature ovarian failure (POF), indicating that normal folliculogenesis requires AR-mediated androgen action. Moreover, these results imply that POF might be caused by impairment of AR-mediated androgen action.

Branched chain alpha-keto acid dehydrogenase, E1-beta subunit gene is associated with premature ovarian failure

Genetic variants of the human branched chain alpha-keto acid dehydrogenase, E1-beta subunit (BCKDHB) gene were identified and they have been associated with premature ovarian failure (POF). Reconstructed haplotype from these variants was also associated with POF.

SirT1 modulates the estrogen-insulin-like growth factor-1 signaling for postnatal development of mammary gland in mice

INTRODUCTION

Estrogen and insulin-like growth factor-1 (IGF-1) play important roles in mammary gland development and breast cancer. SirT1 is a highly conserved protein deacetylase that can regulate the insulin/IGF-1 signaling in lower organisms, as well as a growing number of transcription factors, including NF-kappaB, in mammalian cells. Whether SirT1 regulates the IGF-1 signaling for mammary gland development and function, however, is not clear. In the present study, this role of SirT1 was examined by studying SirT1-deficient mice.

METHODS

SirT1-deficient (SirT1(ko/ko)) mice were generated by crossing a new strain of mice harboring a conditional targeted mutation in the SirT1 gene (SirT1(co/co)) with CMV-Cre transgenic mice. Whole mount and histology analyses, immunofluorescence staining, immunohistochemistry, and western blotting were used to characterize mammary gland development in virgin and pregnant mice. The effect of exogenous estrogen was also examined by subcutaneous implantation of a slow-releasing pellet in the subscapular region.

RESULTS

Both male and female SirT1(ko/ko) mice can be fertile despite the growth retardation phenotype. Virgin SirT1(ko/ko) mice displayed impeded ductal morphogenesis, whereas pregnant SirT1(ko/ko) mice manifested lactation failure due to an underdeveloped lobuloalveolar network. Estrogen implantation was sufficient to rescue ductal morphogenesis. Exogenous estrogen reversed the increased basal level of IGF-1 binding protein-1 expression in SirT1(ko/ko) mammary tissues, but not that of IkappaB alpha expression, suggesting that increased levels of estrogen enhanced the production of local IGF-1 and rescued ductal morphogenesis. Additionally, TNFalpha treatment enhanced the level of the newly synthesized IkappaB alpha in SirT1(ko/ko) cells. SirT1 deficiency therefore affects the cellular response to multiple extrinsic signals.

CONCLUSION

SirT1 modulates the IGF-1 signaling critical for both growth regulation and mammary gland development in mice. SirT1 deficiency deregulates the expression of IGF-1 binding protein-1 and attenuates the effect of IGF-1 signals, including estrogen-stimulated local IGF-1 signaling for the onset of ductal morphogenesis. These findings suggest that the enzymatic activity of SirT1 may influence both normal growth and malignant growth of mammary epithelial cells.

Premature ovarian failure

The diagnosis of premature ovarian failure is based on the finding of amenorrhoea before age 40 associated with follicle-stimulating hormone levels in the menopausal range. Screening for associated autoimmune disorders and karyotyping, particularly in early onset disease, constitute part of the diagnostic work up. There is no role for ovarian biopsy or ultrasound in making the diagnosis. Management essentially involves hormone replacement and infertility treatment, the most successful being assisted conception with donated oocytes. Embryo cryopreservation, ovarian tissue or oocyte cryopreservation and in vitro maturation of oocytes hold promise in cases where ovarian failure is foreseeable as in women undergoing cancer treatments.

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.

Ovarian dysfunction and FMR1 alleles in a large Italian family with POF and FRAXA disorders: case report

Background

The association between premature ovarian failure (POF) and the FMR1 repeat number (41> CGG_n< 200) has been widely investigated. Current findings suggest that the risk estimation for POF can be calculated in the offspring of women with pre-mutated FMR1 alleles.

Case presentation

We describe the coexistence in a large Italian kindred of Fragile X syndrome and familial POF in females with ovarian dysfunctions who carried normal or expanded FMR1 alleles. Genetic analysis of the FMR1 gene in over three generations of females revealed that six carried pre-mutated alleles (61–200), of which two were also affected by POF. However a young woman, who presented a severe ovarian failure with early onset, carried normal FMR1 alleles (<40). The coexistence within the same family of two dysfunctional ovarian conditions, one FMR1-related and one not FMR1-related, suggests that the complexity of familial POF conditions is larger than expected.

Conclusion

Our case study represents a helpful observation and will provide familial cases with heterogeneous etiology that could be further studied when candidate genes in addition to the FMR1 premutation will be available.

Ovulation in a postmenopausal woman

OBJECTIVE

To report the first documented case of ovulation in a postmenopausal woman.

DESIGN

Case study.

SETTING

University reproductive endocrinology and infertility clinic.

PATIENT(S)

A 57-year-old woman, who had been postmenopausal for 3 years and presented with breast tenderness and was found to have laboratory and ultrasound evidence of ovulation.

INTERVENTION(S)

Laboratory evaluation and transvaginal ultrasound.

MAIN OUTCOME MEASURE(S)

Ovulation in a postmenopausal woman.

RESULT(S)

Laboratory evaluations revealed estrogen and progesterone consistent with an ovulatory pattern. Ultrasound revealed a thickened endometrium and a corpus luteum, both of which resolved after menses.

CONCLUSION(S)

This is the first report of ovulation in a postmenopausal woman. This observation opens the door to new questions about the sensitivity of the hypothalamic-pituitary-ovarian axis in menopause as well as about ovarian senescence.

Epigenetic control of the critical region for premature ovarian failure on autosomal genes translocated to the X chromosome: a hypothesis

Chromosomal rearrangements in Xq are frequently associated to premature ovarian failure (POF) and have contributed to define a POF "critical region" from Xq13.3 to Xq26. Search for X-linked genes responsible for the phenotype has been elusive as most rearrangements did not interrupt genes and many were mapped to gene deserts. We now report that ovary-expressed genes flanked autosomal breakpoints in four POF cases analyzed whose X chromosome breakpoints interrupted a gene poor region in Xq21, where no ovary-expressed candidate genes could be found. We also show that the global down regulation in the oocyte and up regulation in the ovary of X-linked genes compared to the autosomes is mainly due to genes in the POF "critical region". We thus propose that POF, in X;autosome balanced translocations, may not only be caused by haploinsufficiency, but also by a oocyte-specific position effect on autosomal genes, dependent on dosage compensation mechanisms operating on the active X chromosome in mammals.

Skewed X-chromosome inactivation is associated with primary but not secondary ovarian failure

Premature ovarian failure (POF) is the occurrence of menopause before the age of 40, and may present with either primary or secondary amenorrhea. Numerous cases of POF in women with X-chromosome deletions or translocations have been reported; thus, it is possible that smaller rearrangements undetectable by conventional cytogenetics may contribute to POF in some patients. In females with an abnormal X chromosome, cells with inactivation of the normal X may be selected against, causing skewed X-chromosome inactivation (XCI). We therefore assessed XCI by methylation sensitive restriction digestion and PCR amplification at the androgen receptor (AR) locus, in 4 primary and 55 secondary POF patients and 109 control women. In samples heterozygous at AR and therefore informative for the skewing assay, the frequency of skewed XCI among the women with secondary amenorrhea was identical to that in control women, with 4 out of 48 (8.3%) secondary ovarian failure patients and 8 out of 97 (8.2%) control women having > or =90% skewing. Notably, all three primary amenorrhea patients that were informative at AR had skewed XCI > or =90% (P = 0.001 vs. control women; Fisher's exact test). To investigate whether X-chromosome copy number alterations were responsible, DNA from selected patients with skewed XCI was examined by high resolution DNA microarray, however no potential regions of DNA addition or deletion were confirmed by FISH or PCR. X-chromosome abnormalities undetectable by array, or reduced follicular pool due to an early trisomic rescue event, may explain the skewed XCI observed in POF patients presenting with primary amenorrhea.

Ovarian granulosa cell survival and proliferation requires the gonad-selective TFIID subunit TAF4b

Oocyte development in the mammalian ovary requires productive interactions with somatic granulosa cells of the ovarian follicle. Proliferating granulosa cells support the progression of follicular growth and maturation, multiplying dramatically as it unfolds. The cell cycle recruitment of granulosa cells is regulated at least in part by hormones such as follicle-stimulating hormone (FSH) and estrogen. Follicles recruited into the growth phase following formation of multiple layers of granulosa cells have two major fates: either to continue proliferation followed by differentiation, or to die by programmed cell death, or atresia. While many of the signaling pathways orchestrating ovarian follicle development are known, the downstream transcriptional regulators that integrate such signals in the mammalian ovary remain to be defined. Recent experiments in diverse organisms have revealed multiple instances of gonad-selective components of the basal transcriptional machinery. One such protein, TAF4b, is a gonadal-enriched coactivator subunit of the TFIID complex required for normal female fertility in the mouse. To determine the etiology of female infertility of the TAF4b-deficient mice, we have determined multiple functions of TAF4b during postnatal ovarian follicle development. Here we demonstrate that the TAF4b protein is expressed in the granulosa cell compartment of the mammalian ovarian follicle. Furthermore, TAF4b-deficient mouse ovaries contain reduced numbers of primordial as well as growing follicles and a concomitant increased proportion of apoptotic follicles in comparison to wild type counterparts. Importantly, TAF4b-null follicles are largely resistant to induction of proliferation in response to multiple hormonal stimuli including estrogen and FSH and demonstrate compromised granulosa cell survival. Together, these data suggest that TAF4b integrates a program of granulosa cell gene expression required for normal ovarian follicle survival and proliferation in response to diverse ovarian signaling events.

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.

Breast cancer treatment and ovarian failure: risk factors and emerging genetic determinants

Most premenopausal women diagnosed with primary breast cancer receive adjuvant chemotherapy, and many experience chemotherapy-induced ovarian failure (CIOF). CIOF is associated with menopausal symptoms, fertility concerns and long-term implications including bone loss. Ironically, CIOF might confer a disease-specific benefit to women whose breast cancers express hormone receptors. Risk factors of CIOF include the woman's age at the time of therapy, and the type, dose and schedule of chemotherapy. Because inherited genetic factors have an important role in determining who will experience CIOF, genetic testing has the potential to provide optimal counselling about risks and possible interventions.

The FMR1 premutation and reproduction

OBJECTIVE

To update clinicians on the reproductive implications of premutations in FMR1 (fragile X mental retardation 1). Fragile X syndrome, a cause of mental retardation and autism, is due to a full mutation (>200 CGG repeats). Initially, individuals who carried the premutation (defined as more than 55 but less than 200 CGG repeats) were not considered at risk for any clinical disorders. It is now recognized that this was incorrect, specifically with respect to female reproduction.

DESIGN AND SETTING

Literature review and consensus building at two multidisciplinary scientific workshops.

CONCLUSION(S)

Convincing evidence now relates the FMR1 premutation to altered ovarian function and loss of fertility. An FMR1 mRNA gain-of-function toxicity may underlie this altered ovarian function. There are major gaps in knowledge regarding the natural history of the altered ovarian function in women who carry the FMR1 premutation, making counseling about reproductive plans a challenge. Women with premature ovarian failure are at increased risk of having an FMR1 premutation and should be informed of the availability of fragile X testing. Specialists in reproductive medicine can provide a supportive environment in which to explain the implications of FMR1 premutation testing, facilitate access to testing, and make appropriate referral to genetic counselors.

Prevalence of premature ovarian failure in monozygotic and dizygotic twins

BACKGROUND

Premature ovarian failure (POF) before 40 years of age from natural causes affects approximately 1% of adult women, with minor variations between ethnic groups. A recent case of ovarian transplantation between young monozygotic (MZ) twins in which one had undergone unexplained POF at 14 years has prompted a study of the prevalence of POF.

METHODS

Menopausal ages of 832 Australian and UK female twin-pairs were extracted from volunteer national twin registry databases containing medical, reproductive and lifestyle data surveyed by mail questionnaire. Surgical menopause was an exclusion criterion.

RESULTS

The prevalence of POF in both MZ and dizygotic (DZ) twins was similar in both registries and 3- to 5-fold greater than the general population at age thresholds 40 and 45 years. No specific factors were found to account for the higher risk of early menopause. Some twins of both zygosities were highly discordant for menopausal age (>or=10 years). Nevertheless, there was significant intra-twin dependence, especially for MZ twins, and the average age difference at last menses was greater in DZ twin-pairs.

CONCLUSION

Both MZ and DZ twins are at higher risk of POF. Despite some striking differences within MZ twin-pairs, menopausal ages were more concordant than for DZ twin-pairs, confirming that the timing of menopause has a heritable component.

Foxl2 function in ovarian development

Foxl2 is a forkhead transcription factor essential for proper reproductive function in females. Human patients carrying mutations in the FOXL2 gene display blepharophimosis/ptosis/epicanthus inversus syndrome (BPES), an autosomal dominant disease associated with eyelid defects and premature ovarian failure in females. Recently, animal models for BPES have been developed that in combination with a catalogue of human FOXL2 mutations provide further insight into its molecular function. Mice homozygous mutant for Foxl2 display craniofacial malformations and female infertility. The analysis of the murine phenotype has revealed that Foxl2 is required for granulosa cell function. These ovarian somatic cells surround and nourish the oocyte and play an important role in follicle formation and activation. Mutations upstream of FOXL2 in humans, not affecting the coding sequence itself, have also been shown to cause BPES, which points to the existence of a distant regulatory element necessary for proper gene expression. The same regulatory sequences may be deleted in the goat polled intersex syndrome (PIS), in which FoxL2 expression is severely reduced. Sequence comparison of FoxL2 from several vertebrate species has shown that it is a highly conserved gene involved in ovary development. Thus, the detailed understanding of Foxl2 function and regulation and the identification of its transcriptional targets may open new avenues for the treatment of female infertility in the future.

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.

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.

Dominant inheritance of premature ovarian failure associated with mutant mitochondrial DNA polymerase gamma

BACKGROUND

Premature ovarian failure (POF) results in menopause before the age of 40. Recently, mutations in the catalytic subunit of mitochondrial DNA polymerase gamma (POLG) were shown to segregate with POF in families with progressive external ophthalmoplegia (PEO) and multiple large-scale rearrangements of mitochondrial DNA (mtDNA).

METHODS AND RESULTS

A patient, mother and maternal grandmother are described, all presenting with POF and PEO. The mother developed parkinsonism in her sixth decade. Normal mtDNA sequence excluded mitochondrial inheritance. Sequence analysis of polymerase gamma revealed a dominant Y955C mutation that segregated with disease. Southern blot analysis demonstrated mtDNA depletion in fibroblasts (43% of controls). In contrast, multiple rearrangements of mtDNA were seen in skeletal muscle, consistent with the relative sparing of nuclear-encoded complex II activity compared with other respiratory chain enzymes. Immunoblotting of native gels showed that DNA polymerase gamma stability was not affected, whereas a reverse-transcriptase primer-extension assay suggested a trend towards reduced polymerase activity in fibroblasts.

CONCLUSIONS

This study confirms that POLG mutations can segregate with POF and parkinsonism and demonstrates for the first time that the Y955C mutation can lead to mtDNA depletion. Future screening projects will determine the frequency with which POLG is involved in the aetiology of POF and its impact on reproductive counselling.

Premature ovarian failure, endothelial dysfunction and estrogen-progestogen replacement

Cardiovascular disease, including coronary artery disease, stroke and peripheral vascular disease, is the leading cause of death among women. Vascular endothelial dysfunction is an early marker of atherosclerosis. Women with premature ovarian failure (or premature menopause) present an increased risk for cardiovascular disease, which might be attributed to the early onset of vascular endothelial dysfunction, associated with sex steroid deficiency. Cyclical estrogen and progestogen therapy has been shown to restore endothelial function in these young women. Further research is required to assess primarily the long-term effects of hormone replacement therapy on cardiovascular and overall prognosis in young women with premature ovarian failure, as well as the effects of different doses, duration and routes of hormone administration in these women.

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.