Genetic disorders in premature ovarian failure

This review presents the genetic disorders associated with premature ovarian failure (POF), obtained by Medline, the Cochrane Library and hand searches of pertinent references of English literature on POF and genetic determinants cited between the year 1966 and February 2002. X monosomy or X deletions and translocations are known to be responsible for POF. Turner's syndrome, as a phenotype associated with complete or partial monosomy X, is linked to ovarian failure. Among heterozygous carriers of the fragile X mutation, POF was noted as an unexpected phenotype in the early 1990s. Autosomal disorders such as mutations of the phosphomannomutase 2 (PMM2) gene, the galactose-1-phosphate uridyltransferase (GALT) gene, the FSH receptor (FSHR) gene, chromosome 3q containing the Blepharophimosis gene and the autoimmune regulator (AIRE) gene, responsible for polyendocrinopathy-candidiasis-ectodermal dystrophy, have been identified in patients with POF. In conclusion, the relationship between genetic disorders and POF is clearly demonstrated in this review. Therefore, in the case of families affected by POF a thorough screening, including cytogenetic analysis, should be performed.     

Ovarian tissue cryopreservation and transplantation: preliminary findings and implications for cancer patients.

Cancer treatment modalities are increasingly more effective in achieving complete remission and cure. Aggressive chemotherapy and radiotherapy, as well as bone marrow transplantation, results in >90% cure in many cancers of children and young women. As a result of this success however, a new problem has arisen. Many young women survive to live the rest of their lives in menopause, and have no chance of conceiving on their own. Oocyte cryopreservation has resulted in a handful of pregnancies, but the technique may not be applicable to young women and children. Ovarian tissue cryopreservation and transplantation has emerged against this background, first in successful rodent studies, and then in sheep and human ovarian xenograft studies. Because of the encouraging results with animals and xenografts, a human ovarian transplantation trial was launched. Pelvic auto-transplantation of frozen-banked ovarian tissue resulted in ovulation in one patient. Several other patients received fresh grafts subcutaneously, and preliminary results indicated antral follicle development at least in one patient. With the addition of promising data from humans, ovarian tissue cryopreservation from selected patients before cancer treatment, and in those requiring oophorectomy for benign causes, is now advocated.     

Cryopreservation of oocytes from pre-antral follicles

Cryobiology is a very important tool in reproductive biology. Research in this area focuses on the possibility of restoring fertility in women with reproductive problems or after cancer treatments. Another goal is to establish a genetic resource bank for endangered or commercially important animal species. Cryopreservation of oocytes from pre-antral follicles has been studied during the past decade. Procedures can be divided between the cryopreservation of either ovarian tissue or isolated follicles. Most studies describe a slow freezing/rapid thawing protocol to cryopreserve ovarian fragments. Histology shows that the follicles maintain their morphological integrity, and transplantation of ovarian tissue demonstrates that the follicles can restart their growth and eventually ovulate. Some research groups have obtained offspring using this procedure in mice and sheep. With regard to the cryopreservation of isolated follicles, the few studies reported in this area used the same freezing protocol, and some of them described follicular growth using in-vitro culture. The best result was obtained in mice, with animal birth after follicular cryopreservation and culture. However, additional studies are necessary for a better understanding of the events during follicular cryopreservation and to establish a standard protocol for ovarian transplantation or follicle culture.     

The effects of radiotherapy and chemotherapy on female reproduction.

High dose chemotherapy and radiotherapy have radically increased long-term survival of young cancer patients, but major side effects of these treatments are ovarian failure and infertility. Knowledge of the risks and probabilities of ovarian failure caused by treatment is crucial for patients and physicians in order to make informed choices that will best serve patients' interests. This review presents data on ovarian damage and failure following exposure to radiotherapy, chemotherapy and ablative therapy. The risk is evaluated from the published literature according to patient's age, treatment protocol and also according to the diagnosis of some common malignancies. Many of these patients will not be sterilized immediately following treatment, but will suffer from premature menopause. In order to prevent sterilization, ovarian transposition before pelvic irradiation is mandatory. Besides cryopreservation of ovarian tissue and embryos before administration of chemotherapy, the possible protective effect of pituitary-ovarian down-regulation is discussed. The mechanism of primordial follicles damage induced by radio/chemotherapy is presented as well as the role of apoptosis signalling pathways underlying destruction. Increased knowledge of these mechanisms could help to identify potential effective inhibitors that can block the path of primordial follicles destruction and reduce ovarian failure rate.     

Female sex preponderance for idiopathic familial premature ovarian failure suggests an X chromosome defect: opinion

Premature ovarian failure (POF) is defined as ovarian failure occurring before the age of 40 years. A genetic aetiology is suggested by the occurrence of families with two or more affected females. We have characterised the pattern of inheritance of 41 cases of familial POF and compared them to published pedigrees. In eleven families a clear genetic association of POF could be identified. In the remaining 30 families the mechanism of inheritance was obscure. We found a female sex preponderance in the siblings of 30 families with idiopathic POF and in previously published series of idiopathic familial POF. In contrast, other known causes of POF, such as blepharophimosis ptosis epicanthus and inversus and autosomal recessive gonadal dysgenesis, had no altered sex ratio. One of our series of 30 pedigrees demonstrated transmission of POF susceptibility through fathers, which we believe is the first to be described in the literature. We present a group of five consanguineous families where we assume the mode of inheritance is autosomal recessive and where there was no female sex preponderance. Female sex preponderance for idiopathic familial POF suggests an X chromosome defect is inherited as a major cause of ovarian failure.     

Regulation of primordial follicle assembly and development

The assembly of the primordial follicles early in ovarian development and the subsequent development and transition of the primordial follicle to the primary follicle are critical processes in ovarian biology. These processes directly affect the number of oocytes available to a female throughout her reproductive life. Once the pool of primordial follicles is depleted a series of physiological changes known as menopause occur. The inappropriate coordination of these processes contributes to ovarian pathologies such as premature ovarian failure (POF) and infertility. Primordial follicle assembly and development are coordinated by locally produced paracrine and autocrine growth factors. Endocrine factors such as progesterone have also been identified that influence follicular assembly. Locally produced factors that promote the primordial to primary follicle transition include growth factors such as kit ligand (KL), leukaemia inhibitory factor (LIF), bone morphogenic proteins (BMP's), keratinocyte growth factor (KGF) and basic fibroblast growth factor (bFGF). Factors mediating both precursor theca-granulosa cell interactions and granulosa-oocyte interactions have been identified. A factor produced by preantral and antral follicles, Müllerian inhibitory substance, can act to inhibit the primordial to primary follicle transition. Observations suggest that a complex network of cell-cell interactions is required to control the primordial to primary follicle transition. Elucidation of the molecular and cellular control of primordial follicle assembly and the primordial to primary follicle transition provides therapeutic targets to regulate ovarian function and treat ovarian disease.     

Antiovarian antibody in premature ovarian failure

Premature ovarian failure is a syndrome consisting of primary or secondary amenorrhoea, hypergonodotropiremia and hypoestrogenemia in women under the age of 40. An autoimmune mechanism was suggested as possible etiology when Vallolton and Forbes in 1966-67 found antibodies to the cytoplasm of rabbit ova in 29 of 232 tested sera. Immune mechanism in the pathogenesis of premature ovarian failure (POF) is suggested by association of autoimmune phenomenon with POF in some cases and demonstration of circulating antibodies to ovary in serum samples from women with POF. The incidence of presence of antiovarian antibody of POF patients has been reported earlier. Evidence of autoimmunity is present in 18-92% of patients with POF. In the present study we have studied 18 cases of POF without any overt manifestation of autoimmune disorder but the antiovarian antibody was detected, with the idea that this autoantibody might be the cause of ovarian dysfunction which is evident in POF. Presence of antiovarian antibody in 16.67% cases with POF in our study that ovarian antibodies may play a role in or reflect an autoimmune process responsible for the development of POF.     

Ovarian tissue cryopreservation and transplantation: a review

The review covers current options for ovarian tissue cryopreservation and transplantation and provides a systematic review of the existing literature from the last 10 years, taking into account all previously published reviews on the subject. The different cryopreservation options available for fertility preservation in cancer patients are embryo cryopreservation, oocyte cryopreservation and ovarian tissue cryopreservation. The choice depends on various parameters: the type and timing of chemotherapy, the type of cancer, the patient's age and the partner status. The different options and their results are discussed, as well as their putative indications and efficacy. The review concludes that advances in reproductive technology have made fertility preservation techniques a real possibility for patients whose gonadal function is threatened by premature menopause, or by treatments such as radiotherapy, chemotherapy or surgical castration.     

EMAS position statement: Managing women with premature ovarian failure

Introduction

Premature ovarian failure (also known as premature menopause) is defined as menopause before the age of 40. It can be “natural” or “iatrogenic” such as after bilateral oophorectomy. It may be either primary or secondary. In the majority of cases of primary POF the cause is unknown. Chromosome abnormalities (especially X chromosome), follicle-stimulating hormone receptor gene polymorphisms, inhibin B mutations, enzyme deficiencies and autoimmune disease may be involved. Secondary POF is becoming more important as survival after treatment of malignancy through surgery, radiotherapy and chemotherapy continues to improve.

Aim

To formulate a position statement on the management of premature ovarian failure.

Materials and methods

Literature review and consensus of expert opinion.

Results and conclusions

Diagnosis should be confirmed with an elevated FSH greater than 40 IU/L and an estradiol level below 50 pmol/L in the absence of bilateral oophorectomy. Further assessment should include thyroid function tests, autoimmune screen for polyendocrinopathy, karyotype (less than 30 years of age) and bone mineral density. Untreated early ovarian failure increases the risk of osteoporosis, cardiovascular disease, dementia, cognitive decline and Parkinsonism. The mainstay of treatment is hormone therapy which needs to be continued until the average age of the natural menopause. With regard to fertility, while spontaneous ovulation may occur the best chance of achieving pregnancy is through donor oocyte in vitro fertilization. It is essential that women are provided with adequate information as they may find it a difficult diagnosis to accept. It is recommended that women with POF are seen in a specialist unit able to deal with their multiple needs.     

Mutations in the coding region of the FOXL2 gene are not a major cause of idiopathic premature ovarian failure

Premature ovarian failure (POF) is a heterogeneous disorder whose aetiology is still unknown. Recently, the autosomal FOXL2 gene, highly expressed in the adult ovary, has been correlated with the disorder. FOXL2 mutations, causing a truncation of the FOXL2 protein in the forkhead domain or in the poly-Ala tract lead to blepharophimosis-ptosis-epicanthus-inversus syndrome associated with POF (BPES I). Interestingly, in two out of 70 idiopathic POF patients, a 30 bp deletion (898-927del) and a missense mutation (1009T-->A) were identified. To further evaluate the correlation between POF and FOXL2 mutations, 120 phenotypically normal women affected by POF were analysed by direct sequencing of the FOXL2 coding region. The analysis did not reveal any mutation in the 240 analysed chromosomes, indicating that mutations in the FOXL2 coding region are rarely associated with non-syndromic POF.     

Ovarian failure and polycystic ovary syndrome

The human ovary is commonly the target of an autoimmune attack leading to the ovarian dysfunction which can be manifested as premature ovarian failure (POF), polycystic ovary syndrome (PCOS), unexplained infertility as well as endometriosis. In case of POF, the evidence for an autoimmune etiology is based on the presence of lymphocytic oophoritis, autoantibodies to ovarian antigens and association with other autoimmune disorders, which was clearly documented in many studies. The search for antiovarian antibodies has been undertaken in numerous studies, especially in patients with POF, however their results are still conflicting particularly due to difference in laboratory methods as well as many ovarian components being potential antigens. On the other side the autoimmune etiology of PCOS is still debated and was documented in some cases. Association of PCOS with non-organ specific autoimmune disorders is controversial; however association with autoimmune thyroid disease was well demonstrated in some studies.     

Turner's syndrome and fertility: current status and possible putative prospects.

Women with Turner's syndrome should be carefully followed throughout life. Growth hormone therapy should be started at age 2-5 years. Hormone replacement therapy for the development of normal female sexual characteristics should be started at age 12-15 years and continued for the long term to prevent coronary artery disease and osteoporosis. Most women with Turner's syndrome have ovarian dysgenesis; therefore, they are usually infertile, and in very rare cases have spontaneous menses followed by early menopause. Only 2% of the women have natural pregnancies, with high rates of miscarriages, stillbirths and malformed babies. Their pregnancy rate in oocyte donation programmes is 24-47%, but even these pregnancies have a high rate of miscarriage, probably due to uterine factors. A possible future prospect is cryopreservation of ovarian tissue containing immature follicles before the onset of early menopause, but methods of replantation and in-vitro maturation still need to be developed. Should these autologous oocytes indeed be used in the future, affected women would need to undergo genetic counselling before conception, followed by prenatal assessment.     

An investigation into FOXE1 polyalanine tract length in premature ovarian failure

Premature ovarian failure (POF) is a common condition affecting 1% of women worldwide. There is strong evidence for genetic involvement in POF as many cases are familial, and mutations in several genes have been associated with POF. We investigated variation in FOXE1 polyalanine tract length, following the observation that polyalanine tract deletions are seen in the closely related FOXL2 in patients with POF. In addition, polyalanine tract expansions in FOXL2 are often seen in patients with blepharophimosis-ptosis-epicanthus inversus syndrome (BPES), a rare eyelid disorder often associated with POF. The FOXE1 polyalanine tract shows marked variation in its length between POF patients and normal controls, existing as an allele of 12, 14, 16, 17 or 19 alanine residues. We found evidence to suggest that variation in FOXE1 polyalanine tract length predisposes to POF.     

Fragile X premutation in women with sporadic premature ovarian failure in Slovenia

BACKGROUND: Fragile X premutation carriers are at increased risk of premature ovarian failure (POF), which is usually defined as menopause before the age of 40 years. METHODS: We evaluated 83 women with sporadic premature ovarian failure, treated at the Department of Obstetrics and Gynaecology, University Medical Centre, Ljubljana, between 1991 and 2001. There was no family history of mental retardation in any of the patients. They were phenotypically normal and had normal female karyotype (46,XX), without a past history of pelvic surgery, chemotherapy or autoimmune diseases. RESULTS: The premutation in the FRAXA locus was found in four of the women screened (4.8%; 95% confidence interval 1.9-11.7). This prevalence (1 in 21) was statistically significantly higher than expected in the female Caucasian population. CONCLUSION: In this study we have confirmed an important association between FRAXA premutation and the pathogenesis of POF. This result has practical implications for genetic counselling and fertility treatment.     

Identification of novel mutations in FOXL2 associated with premature ovarian failure

Premature ovarian failure (POF) affects approximately 1% of women and is known to be caused by sex chromosome abnormalities, iatrogenic agents and autoimmune diseases, but in the majority of cases the cause is unknown. However, several families have been identified as having an inherited predisposition to POF, suggesting a genetic component to the condition in these cases. The FOXL2 gene of 70 POF patients from New Zealand and Slovenia was screened for mutations. In a Slovenian POF patient, a novel 30 bp deletion was identified that was predicted to remove 10 out of 14 alanines (A221_A230del), from the polyalanine tract downstream of the winged helix/forkhead domain of the FOXL2 protein. A novel single nucleotide substitution, 772(1009)T>A, which is predicted to change amino acid 258 from tyrosine to asparagine (Y258N), was identified in a New Zealand POF patient. Neither mutation was identified in 200 normal control chromosomes from 100 control samples. Three previously unreported single nucleotide substitutions, considered to be non-functional polymorphisms, were also identified.     

The accuracy of multivariate models predicting ovarian reserve and pregnancy after in vitro fertilization: a meta-analysis

BACKGROUND: To review the accuracy of multivariate models for the predictionof ovarian reserve and pregnancy in women undergoing IVF comparedwith the antral follicle count (AFC) as single test. METHODS: We performed a computerized MEDLINE and EMBASE search to identifyarticles published on multivariate models for ovarian reservetesting in patients undergoing IVF. In order to be selected,articles had to contain data on the outcome of IVF in termsof either pregnancy and/or poor response and on the predictionof these events based on a multivariate model. For the selectedstudies, sensitivity and specificity of the test in the predictionof poor ovarian response and non-pregnancy were calculated.Overall performance was assessed by estimating a summary receiveroperating characteristic (ROC) curve, which was compared withthe ROC curve for the AFC as the current best single test. RESULTS: We identified 11 studies reporting on the predictive capacityof multivariate models in ovarian reserve testing. All studiesreported on the prediction of poor ovarian response, whereasnone reported on the occurrence of pregnancy. The sensitivityfor prediction of poor ovarian response varied between 39% and97% and the specificity between 50% and 96%. Logistic regressionanalysis indicated that cohort studies provided a significantlybetter discriminative performance than case–control studies.As cohort studies are superior to case–control studies,further analysis was limited to the cohort studies. For thecohort studies, a summary ROC curve could be estimated, whichhad a shape similar to that previously made for the AFC. CONCLUSIONS: The accuracy of multivariate models for the prediction of ovarianresponse in women undergoing IVF is similar to the accuracyof AFC. No data are available on the capacity of these modelsto predict pregnancy, let alone live birth. On the basis ofthese findings, the use of more than one single test for theassessment of ovarian reserve cannot currently be supported.     

Sex steroids and bone: current perspectives

Although the process of bone remodelling or its control has not yet been fully elucidated there is, at present, sufficient information available to conclude that ovarian steroids (estrogens, androgens, progesterone) play an essential role in skeletal homeostasis. The mechanism of action of sex steroids on the skeleton is still not entirely clear, but it has traditionally included indirect effects on systemic hormones that regulate calcium balance and a direct receptor-mediated action. More recently, changes in cytokine production within the bone marrow, as well as pro-apoptotic and anti-apoptotic effects in the osteoblastic cells, have been proposed as new perspectives on the cellular and molecular mechanisms by which sex steroids influence adult bone homeostasis. Mechanical loading, when combined with estrogens or androgens, results in a greater osteogenic response than either condition separately. Women are especially at risk for osteoporosis if they have had a premature or surgical menopause and have not received hormone replacement therapy (HRT). Other reproductive factors that can help to identify women with osteopenia and emphasize the role of sex steroids in preserving bone mass in premenopausal women include: age at menarche, menstrual history and irregularities (including those associated with excessive exercise), age at menopause, previous hysterectomy, hyperprolactinaemia, anorexia nervosa, scoliosis, ovarian dysgenesis, pregnancy and lactation, and pharmacological ovarian suppression. The prevention of osteoporosis starts with the onset of the menarche. A combination of exercise, appropriate nutrition and a healthy lifestyle all maximize bone mineral accrual and result in optimal peak bone mass; normal ovarian function is essential to this process. Unfortunately, many women actually become aware of the need for osteoporosis prevention much later in life, usually after they have already become menopausal. HRT, however, has important limitations for prevention of fractures in post-menopausal women. Future perspectives for treatment of osteoporosis include androgen therapy and anabolic agents. Specifically, synthetic ligands of the estrogen receptor that can evoke the non-genotrophic but not the genotrophic signal of the receptor may be bone anabolic agents, as opposed to natural estrogens or selective estrogen receptor modulators that are anti-resorptive agents. The same ligands may circumvent the side effects associated with conventional HRT.     

Clinical management of low ovarian response to stimulation for IVF: a systematic review

Poor response is not a rare occurrence in ovarian stimulation. Although not fully accepted, the most dominant criteria for poor ovarian response are small numbers of follicles developed or oocytes retrieved, and low estradiol (E2) levels after the use of a standard stimulation protocol. There is no ideal predictive test as the poor responder is revealed only during ovulation induction; however, increased levels of day 3 FSH and E2 as well as decreased levels of inhibin B can be used to assess ovarian reserve. Several protocols have been proposed for clinical management of low ovarian response in IVF. Although high doses of gonadotrophins have been used by the vast majority of authors, results have been controversial and prospective randomized studies have shown little or no benefit. The few available relevant studies do not indicate that recombinant FSH improves outcome. Flare-up GnRH agonist protocols (including all dosage varieties) produce better results than standard long luteal protocols. Luteal initiation GnRH agonist 'stop' protocols were shown to improve ovarian response according to prospective studies with historical controls, but this was not confirmed by well-designed prospective, randomized, controlled studies. The few available data obtained with GnRH antagonists have not shown any benefits. Adjuvant therapy with growth hormone (GH) or GH-releasing factors results in no significant improvement. The use of corticosteroids reduces the incidence of poor ovarian response in women undergoing IVF treatment. The limited data obtained with nitric oxide donors are encouraging. Pretreatment with combined oral contraceptives prior to stimulation may help ovarian response. No benefit was observed with standard use of ICSI or assisted hatching of zona pellucida. Finally, natural cycle IVF has produced results which are comparable with those obtained with stimulated cycles in true poor responders. Well-designed, large-scale, randomized, controlled trials are needed to assess the efficacy of these different management strategies.     

Effect of overweight and obesity on assisted reproductive technology--a systematic review

Obesity is known to be associated with sub-optimal reproductive performance but its direct effect on the outcome of assisted reproduction techniques (ART) is less clear. This present study aimed to perform a systematic review of the available evidence to assess the effects of obesity on the outcome of ART. A number of observational studies were identified. Interpretation of the results was compromised by variations in the methods used to define overweight and obese populations and inconsistencies in the choice and definition of outcome measures. Compared with women with a BMI of 25 kg/m(2) or less, women with a BMI > or = 25 kg/m(2) have a lower chance of pregnancy following IVF [odds ratio (OR) 0.71, 95% CI: 0.62, 0.81], require higher dose of gonadotrophins (weighed mean differences 210.08, 95% CI: 149.12, 271.05) and have an increased miscarriage rate (OR 1.33, 95% CI: 1.06, 1.68). There is insufficient evidence on the effect of BMI on live birth, cycle cancellation, oocyte recovery and ovarian hyperstimulation syndrome. Further studies with clear entry criteria and uniform reporting of outcomes are needed to investigate the true impact of weight on the outcome of ART.     

Epidemiology and prevention of ovarian hyperstimulation syndrome (OHSS): a review

Ovarian hyperstimulation syndrome (OHSS) is a rare iatrogenic complication of ovarian stimulation occurring during the luteal phase or during early pregnancy. Fortunately, the reported prevalence of the severe form of OHSS is small, ranging from 0.5 to 5%. Nevertheless, as this is an iatrogenic complication of a non-vital treatment with a potentially fatal outcome, the syndrome remains a serious problem for specialists dealing with infertility. The aim of this literature review was to determine whether it is possible to identify patients at risk, and which preventive method should be applied when an exaggerated ovarian response occurs. Data pertaining to the epidemiology and prevention of OHSS in women were searched using Medline, Current Contents and PubMed, and are summarized. Preventive strategies attempt either to limit the dose or concentration of hCG or to find a way to induce luteolysis without inducing a detrimental effect on endometrial and oocyte quality. The following particular preventive strategies were reviewed: cancelling the cycle; coasting; early unilateral ovarian follicular aspiration (EUFA); modifying the methods of ovulation triggering; administration of glucocorticoids, macromolecules and progesterone; cryopreservation of all embryos; and electrocautery or laser vaporization of one or both ovaries.