Premature ovarian failure and fragile X premutation: a study on 45 women

K. T, Justin Margret J, Venkataraman V, Natarajan Padmavathy K, Srisailapathy CRS. FMR1 gene CGG repeat distribution among the three individual cohorts with intellectual disability, autism, and primary ovarian insufficiency from Tamil Nadu, Southern India

Fragile X syndrome is the most common genetic cause of intellectual disability (ID) and is also well known to have a role in primary ovarian insufficiency (POI) and fragile X-associated tremor ataxia syndrome (FXTAS) that expresses across generations. The objective was to compare the CGG repeat variants in FMR1 gene among three correlating cohorts of ID, autism and idiopathic POI. Thirty-six patients with ID, 12 with autism spectrum disorder (ASD) and 13 females with idiopathic POI were screened for FMR1 CGG repeat size by fluorescent methylation-specific PCR and GeneScan analysis, irrespective of Hagerman checklist clinical scores. Among 29 males and seven females, 11 FMR1 allelic variants ranging from 21 to >200 CGG repeats were observed. Three (CF2-3, 39-5, 44-2) out of 29 males had full mutation alleles accounting for a 10.34% incidence of FXS among idiopathic ID males. One of them was a mosaic for CGG repeats with both premutation and full mutation alleles. The frequency of fragile X syndrome is high among patients with idiopathic ID; they also had a high score for the clinical check list. A cascade testing that begins with checklist evaluation prior to DNA analysis will be cost-effective for establishing early diagnosis in South India. With the huge disease burden, there is a need for the establishment of more molecular diagnostics and self-help groups for fragile X syndrome.

Premature ovarian insufficiency: pathogenesis and therapeutic potential of mesenchymal stem cell

Primary ovarian insufficiency (POI) is defined as a reduction in ovarian function before the expected age of menopause. POI is known to increase the risk of cardiovascular disorders, osteoporosis, cognitive decline, and mood disorders, resulting in a reduced quality of life. Appropriate hormone replacement for premenopausal women decreases these adverse health risks and improves quality of life for women with POI, but does not prolong life expectancy. The potential etiologies of POI include chromosomal abnormalities and genetic mutations, autoimmune factors, and iatrogenic causes, including surgery, chemotherapy, and radiation therapy. A major association is suggested to exist between reproductive longevity and the DNA damage pathway response genes. DNA damage and repair in ovarian granulosa cells is strongly associated with POI. Depletion of oocytes with damaged DNA occurs through different cell death mechanisms, such as apoptosis, autophagy, and necroptosis, mediated by the phosphatase and tensin homolog (PTEN)/phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/forkhead transcription factors 3 (FOXO3) pathway. Mesenchymal stem cells (MSCs) are characterized by the ability of self-renewal and differentiation and play an important role in the regeneration of injured tissues. Transplantation of MSCs has been shown to functionally restore ovarian reserve in a POI mouse model. Recent advances in stem cell therapy are likely to be translated to new therapeutic options bringing new hope to patients with POI. The aim of this review is to summarize the pathogenic mechanisms that involve cell death and DNA damage and repair pathways and to discuss the stem cell-based therapies as potential therapeutic options for this gynecologic pathology.

Fragile X syndrome and fragile X-associated tremor ataxia syndrome

Fragile X-associated disorders encompass several conditions, which are caused by expansion mutations in the fragile X mental retardation 1 (FMR1) gene. Fragile X syndrome is the most common inherited etiology of intellectual disability and results from a full mutation or >200 CGG repeats in FMR1. It is associated with developmental delay, autism spectrum disorder, and seizures. Fragile X-associated tremor/ataxia syndrome is a progressive neurodegenerative disease that occurs in premutation carriers of 55-200 CGG repeats in FMR1 and is characterized by kinetic tremor, gait ataxia, parkinsonism, executive dysfunction, and neuropathy. Fragile X-associated primary ovarian insufficiency also occurs in premutation carrier women and manifests with infertility and early menopause. The diseases constituting fragile X-associated disorders differ mechanistically, due to the distinct molecular properties of premutation versus full mutations. Fragile X syndrome occurs when there is a lack of fragile X mental retardation protein (FMRP) due to FMR1 methylation and silencing. In fragile X-associated tremor ataxia syndrome, a toxic gain of function is postulated with the production of excess CGG repeat-containing FMR1 mRNA, abnormal translation of the repeat sequence leading to production of polyglycine, polyalanine, and other polypeptides and to outright deficits in translation leading to reduced FMRP at larger premutation sizes. The changes in underlying brain chemistry due to FMR1 mutations have led to therapeutic studies in these disorders, with some progress being made in fragile X syndrome. This paper also summarizes indications for testing, genetic counseling issues, and what the future holds for these disorders.

Molecular Characterization of FMR1 Gene by TP-PCR in Women of Reproductive Age and Women with Premature Ovarian Insufficiency

BACKGROUND

Fragile X syndrome is caused by CGG repeat expansion mutation in the FMR1 gene. Normal alleles have 5-44 CGG repeats with AGG interruptions. The expanded gray zone (GZ) (45-54 repeats) and premutation (PM) (55-200 repeats) alleles are often uninterrupted and are unstably inherited in subsequent generations. The prevalence of PM and GZ carriers is high in the female population, at 1/66 and 1/113, respectively, and PM is associated with fertility problems in 20% of cases.

OBJECTIVE

Our objective was to molecularly characterize CGG repeats and AGG interruption sequences in the FMR1 gene in women of reproductive age and in women with premature ovarian insufficiency (POI).

MATERIALS AND METHODS

We conducted molecular analysis of the FMR1 gene from 300 women of reproductive age and 140 women with POI using triplet primed-polymerase chain reaction. This enabled us to identify carriers and to document CGG repeat size and the AGG interruption pattern.

RESULTS

In women of reproductive age, 1.7% were GZ carriers and 0.3% were PM carriers; in women with POI, 3.6% were GZ carriers and 2.14% were PM carriers. The frequency of GZ and PM carriers did not significantly differ between the cohorts (Fisher's exact test: p < 2.23 for GZ vs. control and p < 0.101 for PM vs. control). Carriers received genetic counselling; family screening identified an additional seven carriers.

CONCLUSION

We documented preliminary data on the prevalence of GZ and PM carriers among the studied cohorts. The identification of PM carriers among women with POI serves a dual purpose of recognizing a cause for ovarian dysfunction and enabling genetic counselling, which will help carriers when making reproductive decisions.

Distribution of FMR1 and FMR2 Repeats in Argentinean Patients with Primary Ovarian Insufficiency

The premutation state of FMR1 (Fragile X Mental Retardation 1) has been associated with primary ovarian insufficiency (POI), and is the most common known genetic cause for 46,XX patients. Nevertheless, very few studies have analyzed its frequency in Latin American populations. Additionally, a relationship between alleles carrying a cryptic microdeletion in the 5’UTR of FMR2 and the onset of POI has only been studied in one population. Our aim was to analyze the incidence of FMR1 premutations and putative microdeletions in exon 1 of FMR2 in a cohort of Argentinean women with POI. We studied 133 patients and 84 controls. Fluorescent PCR was performed, and the FMR2 exon 1 was further sequenced in samples presenting less than 11 repeats. We found the frequency of FMR1 premutations to be 6.7% and 2.9% for familial and sporadic patients, respectively. Among controls, 1/84 women presented a premutation. In addition, although we did not find microdeletions in FMR2, we observed a change (T >C) adjacent to the repeats in two sisters with POI. Given the repetitive nature of the sequence involved, we could not ascertain whether this represents a single nucleotide polymorphism (SNP) or a deletion. Therefore, a relationship between FMR2 and POI could not be established for our population.

FMR1 premutation: not only important in premature ovarian failure but also in diminished ovarian reserve

It is recognized that FMR1 premutation expansions are associated with premature ovarian failure (POF), but their role in diminished ovarian reserve (DOR) is not clearly established. Moreover, the impact of smaller repeats at the boundary of premutation and normal is less clear. Therefore, we have compared the frequency of these intermediate (45-54 repeats) and premutation (>55) sized FMR1 CGG repeats among a patients group including 188 DOR and 173 POF women and 200 controls. FSH and LH concentrations were also compared between intermediate and premutation ranges in patients. The 5' UTR of FMR1 gene was amplified using PCR. The numbers of trinucleotide repeats were confirmed by the Sanger sequencing method. The frequency of premutation was higher in POF and DOR patients in comparison with controls, but the difference in the incidence of intermediate alleles was not statistically significant among these groups. The mean level of serum FSH was higher in patients with premutation than patients with intermediate alleles. Based on the current evidence, we concluded that intermediate-sized FMR1 CGG repeat alleles should not be considered as a high-risk factor for POF and DOR.

The impact of FMR1 gene mutations on human reproduction and development: a systematic review

PURPOSE

This is a comprehensive review of the literature in this field attempting to put the FMR1 gene and its evaluation into context, both in general and for the reproductive health audience.

METHODS

Online database search of publications with systematic review of all papers relevant to ovarian reserve and assisted reproduction was done.

RESULTS

Relevant papers were identified and assessed, and an attempt was made to understand, rationalize and explain the divergent views in this field of study. Seminal and original illustrations were employed.

CONCLUSIONS

FMR1 is a highly conserved gene whose interpretation and effect on outcomes remains controversial in the reproductive health setting. Recent re-evaluations of the commonly accepted normal range have yielded interesting tools for possibly explaining unexpected outcomes in assisted reproduction. Fragile X investigations should perhaps become more routinely assessed in the reproductive health setting, particularly following a failed treatment cycle where oocyte quality is thought to be a contributing factor, or in the presence of a surprise finding of diminished ovarian reserve in a young patient.

Analysis of FMR1 gene premutation and X chromosome cytogenetic abnormalities in 100 Tunisian patients presenting premature ovarian failure

OBJECTIVE

To evaluate the prevalence of FMR1 premutations and X chromosome cytogenetic abnormalities in a large cohort of Tunisian women with premature ovarian failure (POF).

PATIENTS AND METHODS

The cohort consisted of 127 Tunisian women with POF referred by endocrinologists and gynecologists for genetic investigation in the context of idiopathic POF and altered hormonal profiles. Clinical information concerning the reproductive function in the family, previous hormonal measurements and/or possible fertility treatment were collected. Karyotype, FISH analyses, FMR1 and FMR2 testing were performed for all patients.

RESULTS

Fifteen patients (11.81%) presented structural or numerical X chromosomal abnormalities. Moreover, we detected in 12 patients (10.71%) a high level of X mosaicism. Analysis of FMR1 gene in the 100 patients without X chromosomal abnormalities showed that five percent of the patients carried a FMR1 premutation allele. On the other hand, the FMR2 screening did not reveal any deletion.

CONCLUSION

Our study confirms the major role of X chromosome abnormalities in POF and highlights the importance of karyotype analyses and FMR1 screening. These investigations provide valuable information for diagnosis and genetic counseling for these women who still have a 5% chance of spontaneous conception.

The Stage- and Cell Type-Specific Localization of Fragile X Mental Retardation Protein in Rat Ovaries

Premutations of the fragile X mental retardation 1 (FMR1) gene are associated with increased risk of primary ovarian insufficiency. Here we examined the localization of the Fmr1 gene protein product, fragile X mental retardation protein (FMRP), in rat ovaries at different stages, including fetus, neonate, and old age. In ovaries dissected from 19 days postcoitum embryos, the germ cells were divided into 2 types: one with decondensed chromatin in the nucleus was FMRP positive in the cytoplasm, but the other with strongly condensed chromatin in the nucleus was FMRP negative in the cytoplasm. The FMRP was predominantly localized to the cytoplasm of oocytes in growing ovarian follicles. Levels of FMRP in oocytes from elderly (9 or 14 months of age) ovaries were lower than in those from younger ovaries. These results suggest that FMRP is associated with the activation of oogenesis and oocyte function. Especially, FMRP is likely to be implicated in germline development during oogenesis.

Current Concepts in Premature Ovarian Insufficiency

Premature ovarian insufficiency (POI) is a life-changing diagnosis, with profound physical and psychological consequences. Unfortunately, there are many deficiencies in our understanding of the condition as the underlying etiology and optimum management strategies are poorly understood. Improved awareness of POI and its long-term implications has led to increased research interest in recent years. Current research has allowed a greater understanding of the changing epidemiology in POI, genetic factors in its etiology and randomized controlled trials of hormone therapy are underway to provide evidence for treatment. This article reviews the latest literature on POI to summarize current understanding and future directions.

Intermediate CGG repeat length at the FMR1 locus is not associated with hormonal indicators of ovarian age

OBJECTIVE

Premutation and intermediate CGG repeat length at the fragile X mental retardation 1 (FMR1) locus have been associated with premature ovarian failure. We tested whether intermediate length is associated with indicators of ovarian age in a sample of fertile women. Our primary measures of ovarian age were antimüllerian hormone (AMH) and follicle-stimulating hormone (FSH) levels.

METHODS

The cross-sectional sample comprised 258 women with karyotyped spontaneous abortions (140 trisomic spontaneous abortions and 118 chromosomally normal spontaneous abortions or spontaneous abortions with anomalies other than trisomy) and 325 women with recent live births (LBs). We analyzed data from the total sample and data from LBs only. We defined CGG repeat length by the length (both continuous and categorical) on the longer allele.

RESULTS

CGG repeat length was not significantly associated with either hormone measure. A repeat length of 35 to 54 CGG, versus the modal category of 30 CGG, was associated with an approximately 7% increase in median AMH level and a 3% increase in median FSH level. Results were unaltered when analyses were limited to LBs. Analyses of hormone levels using cutpoints to define older ovarian age showed no associations with repeat length. Among 10 women with repeat lengths of 35 to 54 CGG analyzed for AGG sequences, the uninterrupted CGG length was not significantly longer among women with hormonal indicators of "old" versus "young" ovarian age.

CONCLUSIONS

Our data do not support an association between intermediate CGG repeat length and levels of AMH or FSH among fertile women.

Approaches to identify genetic variants that influence the risk for onset of fragile X-associated primary ovarian insufficiency (FXPOI): a preliminary study

Fragile X-associated primary ovarian insufficiency (FXPOI) is due to an X-linked mutation that results from the expansion of a CGG repeat sequence located in the 5′ untranslated region of the FMR1 gene (premutation, PM). About 20% of women who carry the PM have cessation of menses before age 40, a clinical condition known as premature ovarian failure (POF). This leads to a 20-fold increased risk over women in the general population. Thus, this single gene mutation has a major effect on reducing a woman's reproductive life span. Based on survival analysis of about 1300 women, we showed that the mean age at menopause among PM carriers is reduced compared with noncarriers, even after removing women who reported POF. This suggests that the majority of women with the PM, not just a subset, experience ovarian insufficiency earlier than noncarriers. To better understand the underlying mechanism of the PM and to identify genes that modify the variable expressivity of FXPOI, we conducted two pilot studies. The first focused on five common variants known to reduce age at menopause. We genotyped these SNPs in 72 women with a PM who experienced menopause and found a significant association with the total SNP risk burden and age at menopause. This suggests that these SNPs influence onset of FXPOI, after adjusting for the effect of the PM allele. In the second approach, we conducted whole genome sequencing on 10 PM carriers, five with onset of FXPOI prior to age 30 and five who experienced menopause after age 47 years. Although only a pilot study, we describe our preliminary approach to identify potential variants that may play a role in modifying onset of FXPOI and potentially play a role in idiopathic primary ovarian insufficiency. The overarching goal of both approaches is to identify predictor variants that may identify women predisposed to early onset FXPOI and to further identify genes involved in defining a woman's reproductive life span.

The FMR1 gene, infertility, and reproductive decision-making: a review

The strongest association between FMR1 and the ovary in humans is the increased risk of premature ovarian failure (POF) in women who carry the premutation level of CGG repeats (55–199 CGGs). Research on the FMR1 gene has extended to other endpoints of relevance in the OB/GYN setting for women, including infertility and ovarian hormones. After reviewing the nomenclature changes that have occurred in recent years, this article reviews the evidence linking the length of the FMR1 repeat length to fertility and ovarian hormones (follicle stimulating hormone and anti-mullerian hormone as the primary methods to assess ovarian reserve in clinical settings). The literature is inconsistent on the association between the FMR1 trinucleotide repeat length and infertility. Elevated levels of follicle stimulating hormone have been found in women who carry the premutation; however the literature on the relationship between anti-mullerian hormone and the CGG repeat length are too disparate in design to make a summary statement. This article considers the implications of two transgenic mouse models (FXPM 130R and YAC90R) for theories on pathogenesis related to ovarian endpoints. Given the current screening/testing recommendations for reproductive age females and the variability of screening protocols in clinics, future research is recommended on pretest and posttest genetic counseling needs. Future research is also needed on ovarian health measurements across a range of CGG repeat lengths in order to interpret FMR1 test results in reproductive age women; the inconsistencies in the literature make it quite challenging to advise women on their risks related to FMR1 repeat length.

Genetic association studies in female reproduction: from candidate-gene approaches to genome-wide mapping

Many genetic association studies have been performed to investigate disorders of female reproduction, such as polycystic ovary syndrome, premature ovarian failure and endometriosis. These disorders typically manifest heterogeneously, and their pathogeneses are influenced by polygenic and environmental factors. Researchers evaluating these genetic associations have chosen candidate genes related to hormone action, steroid biosynthesis, inflammatory cytokines and autoimmune factors. Several of these genes have yielded statistically significant associations with female reproductive disorders; however, few associations have been robust and reproducible. Whole-genome association studies generate more reliable and unbiased results and represent a breakthrough in genetic studies of female reproduction. Nevertheless, to date only a very small fraction of the overall heritability has been identified and so further studies are needed.

Ovarian abnormalities in a mouse model of fragile X primary ovarian insufficiency

FMR1 premutation (PM) alleles have 55-200 CGG·CCG-repeats in their 5' UTR. PM carriers are at risk of fragile X-associated tremor and ataxia syndrome (FXTAS). Females are also at risk for FX primary ovarian insufficiency (FXPOI). PM pathology is generally attributed to deleterious properties of transcripts with long CGG-tracts. For FXPOI, hormone changes suggest a reduced residual follicle pool. Whether this is due to a smaller than normal original follicle pool or an increased rate of follicle depletion is unclear. A FX-PM mouse the authors generated with 130 CGG·CCG-repeats in the endogenous Fmr1 gene recapitulates features of FXTAS. Here the authors demonstrate that the gross development of the ovary and the establishment of the primordial follicle pool is normal in these mice. However, these animals show a faster loss of follicles of all follicle classes, suggesting that the problem is intrinsic to the ovary. In addition, many oocytes show aberrant nuclear accumulation of FMRP and elevated levels of ubiquitination. Furthermore, PM follicles are smaller and have fewer granulosa cells (GCs) than normal. Thus, these animals have ovarian abnormalities involving both the oocytes and GCs that may shed light on the molecular basis of FXPOI in humans.

Trisomic pregnancy and intermediate CGG repeat length at the FMR1 locus

BACKGROUND

We hypothesized that trisomy arises as a function of the size of the oocyte pool, with risk increased among women with diminished pools. Diminished pools may cause primary ovarian failure, which has been associated with premutation and intermediate CGG repeat length at the Fragile X mental retardation (FMR1) locus. Thus, we hypothesized that the risk of trisomic pregnancy is increased among women with intermediate CGG repeat length on the FMR1 gene.

METHODS

The analysis drew on data from two hospital-based case-control studies. We compared 207 women with trisomic spontaneous abortions (SAs) to three comparison groups: 82 women with other chromosomally abnormal SAs, 99 women with chromosomally normal SAs and 537 women with live births (LBs), age matched to women with SAs. We defined the length of the CGG repeat in four ways: the biallelic mean, the genotypic mean, the length on allele 2 and the length on allele 1. We analyzed CGG repeat length as a categorical variable. All analyses were adjusted for site, age and ethnicity.

RESULTS

CGG repeat length did not differ significantly between women with trisomic SAs and any of the three comparison groups. For the biallelic mean, the adjusted odds ratio relating trisomy (versus LB controls) to the highest category (35.5-59.5 repeats) versus the modal category (26.5-30.0 repeats) was 1.5 (95% confidence interval (CI): 0.7, 3.1). Comparisons with the two SA control groups also showed increased odds of more repeats among trisomy cases. Results were similar when repeat length was defined by the genotypic mean or by the repeat length on allele 2. For allele 1, the odds of short (9-19) repeat length were lower, but not significantly so, for trisomy cases compared with LB controls. Excluding women with premutations (n= 2) from the analysis yielded an adjusted odds ratio of 1.4 (95% CI: 0.7, 2.9) for the biallelic mean.

CONCLUSIONS

Our data are equivocal. The direction of associations is consistent with the hypothesis that repeat length in the intermediate range is associated with trisomy. However, differences between the trisomy cases and the comparison groups are neither large nor statistically significant. Our data rule out odds ratios larger than about 3.

Increased frequency of occult fragile X-associated primary ovarian insufficiency in infertile women with evidence of impaired ovarian function

BACKGROUND

The FMR1 premutation is associated with overt primary ovarian insufficiency (POI). However, its prevalence in women with occult POI (i.e. menstrual cycles, but impaired ovarian response) has not been examined. We hypothesized that both the FMR1 premutation and intermediate allele is more frequent in infertile women with occult POI than in controls, and that a repeat length cutoff might predict occult POI.

METHODS

All subjects were menstruating women <42 years old and with no family history of unexplained mental retardation, autism or fragile X syndrome. Cases had occult POI defined by elevated FSH or poor response to gonadotrophin therapy (n = 535). Control subjects (n = 521) had infertility from other causes or were oocyte donors. Prevalence of the FMR1 premutation and intermediate alleles was examined and allele length was compared between controls and women with occult POI.

RESULTS

The frequency of the premutation (7/535 versus 1/521; P< 0.05) and intermediate alleles (17/535 versus 7/521; P< 0.05) was higher in women with occult POI than in controls. The allele with the greatest number of CGG repeats was longer in women with occult POI compared with controls (32.7 ± 7.1 versus 31.6 ± 4.3; P < 0.01). A receiver operating characteristic curve examining repeat length as a test for occult POI had an area of 0.56 ± 0.02 (P < 0.01). A repeat cutoff of 45 had a specificity of 98%, but a sensitivity of only 5% to identify occult POI. The positive predictive value was only 21% for a fertility population that has ∼ 22% of its patients with occult POI.

CONCLUSIONS

The data suggest that FMR1 premutations and intermediate alleles are increased in women with occult POI. Thus, FMR1 testing should be performed in these women as some will have fragileX-associated POI. Although the FMR1 repeat lengths were longer in women with occult POI, the data do not support the use of a repeat length cutoff to predict occult POI.

Ovarian function in girls and women with GALT-deficiency galactosemia

Primary or premature ovarian insufficiency (POI) is the most common long-term complication experienced by girls and women with classic galactosemia; more than 80% and perhaps more than 90% are affected despite neonatal diagnosis and careful lifelong dietary restriction of galactose. In this review we explore the complexities of timing and detection of galactosemia-associated POI and discuss potential underlying mechanisms. Finally, we offer recommendations for follow-up care with current options for intervention.

Chromosomal abnormalities in women with premature ovarian failure

Premature ovarian failure is a complex disorder that results in the early loss of ovarian function; however this disease must be separated from early menopause because these patients can sporadically ovulate and in literature are described pregnancies. The aetiology and the patho-physiology of premature ovarian failure are still matter of debate, but is commonly accepted that genetic factors play an important role. This review is aimed to present an overview of known inherited factor implied in the pathogenesis of this disorder to help physician in the counselling of affected pregnant women.

Hormone replacement therapy and successful pregnancy in a patient with premature ovarian failure

Premature ovarian failure (POF), premature ovarian insufficiency, premature menopause or hypergonadotropic hypogonadism, a serious life-changing condition that affects young women, remains an enigma and the researcher's challenge. In the present article we described a case of singleton pregnancy in a 33-year-old patient, presenting with POF and treated with hormone replacement therapy. Twenty months later this therapy led to maturation of one follicle, recruitment and fertilisation of the residual oocyte and spontaneous pregnancy ensued. A normal infant was delivered by cesarean section.

Reproductive health of adolescent girls who carry the FMR1 premutation: expected phenotype based on current knowledge of fragile x-associated primary ovarian insufficiency

The fragile X mental retardation 1 (FMR1) gene, located on the X chromosome, is characterized by a dynamic CGG repeat expansion in the 5' untranslated region. It has long been known that female carriers of the FMR1 premutation allele (55-199 CGG) are at risk for passing the FMR1 full mutation (> or =200 repeats) to their offspring, which results in a common form of mental retardation known as fragile X syndrome. The FMR1 premutation allele, however, also places female carriers at significantly increased risk for prematurely diminished ovarian function, which we refer to as fragile X-associated primary ovarian insufficiency (FXPOI). Although of particular concern for younger women, to date, studies of FXPOI have been restricted to women > or =18 years of age and have not specifically addressed ovarian reserve and menstrual cycle characteristics among adolescent carriers. We discuss the expected reproductive phenotype among FMR1 premutation carriers during adolescence, the associated health considerations based on our current understanding of FXPOI, and the directions for future studies.

Fertility preservation in patients with non-oncological conditions

In addition to cancers, many non-oncological conditions, including chromosomal abnormalities and autoimmune disorders, are currently treated with gonadotoxic agents that can lead to premature ovarian failure. Because of the young age of some of the women affected by these conditions, attempts to preserve fertility and ovarian function are recommended. To date, retrieval of immature oocytes followed by in-vitro maturation and vitrification has been found to be especially useful for women who cannot undergo ovarian stimulation, or when there is a contraindication.

The fragile X continuum: new advances and perspectives

Fragile X syndrome is the world's most common hereditary cause of intellectual disability in men and to a lesser extent in women. The disorder is caused by the silencing of a single gene on the X chromosome, the Fragile X Mental Retardation Gene-1. A substantial body of research across the disciplines of molecular genetics, child psychiatry and developmental neuroscience bears testament to a decade of exciting and innovative science that has advanced our knowledge about the fragile X 'signature' or influence across cognitive and social development. The core aims of this review are to first discuss fragile X syndrome and premutation involvement in the context of current advances that demonstrate the dynamic nature of the genotype on phenotypic outcomes. Second, to discuss the implications of these recent advances for the development of clinical and educational interventions and resource tools that target specific phenotypic 'signatures' within the fragile X continuum.

Spontaneous premature ovarian failure: management challenges

Premature ovarian failure (POF) generally describes a syndrome consisting of amenorrhea, sex steroid deficiency, and elevated/menopausal levels of ganadotropins in a woman aged more than two standard deviations below the mean age at menopause estimated for the reference population. Numerous questions relating to this condition remain unanswered, and several important management issues are yet to be addressed. The challenges posed by this important condition range from difficulties with nomenclature to the absence of standardized diagnostic criteria and management guidelines. In the present paper we discuss the management of spontaneous premature ovarian failure, highlight the challenging issues, review the current literature and propose a practical management outline based on our local practice. Women with POF have unique needs that require special attention. There is an urgent need for a more suitable terminology and evidence-based guidelines on which to establish the diagnosis and manage this difficult condition.

Anti-Mullerian hormone indicates early ovarian decline in fragile X mental retardation (FMR1) premutation carriers: a preliminary study

BACKGROUND

Women who carry the fragile X mental retardation (FMR1) premutation are at risk for fragile X-associated primary ovarian insufficiency. Past studies have shown that carriers who are still cycling have increased levels FSH compared with non-carriers. As anti-Mullerian hormone (AMH) has been shown as an excellent marker of ovarian decline, we examined AMH levels among premutation carriers to characterize their ovarian function.

METHODS

We determined the level of FSH and AMH in serum samples collected during early follicular phase from women who carried longer FMR1 repeat alleles (defined as >or=70 repeats, n = 40) and those with shorter repeat alleles (<70 repeats, n = 75), identified by DNA analysis. Comparisons were made stratified by age and carrier status.

RESULTS

For all age groups, AMH levels were significantly lower among longer repeat allele carriers compared to shorter repeat allele carriers (P = 0.002, 0.006 and 0.020 for women ages 18-30, 31-40 and 41-50 years, respectively). In contrast, increased FSH indicative of early ovarian decline was only evident for longer repeat allele carriers aged 31-40 years (P = 0.089, 0.001 and 0.261 for women ages 18-30, 31-40 and 41-50 years, respectively).

CONCLUSIONS

These preliminary data suggest that AMH levels indicate early ovarian decline among women with longer FMR1 repeat alleles; moreover, AMH appears to be a better marker than FSH in identifying this early decline.

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.

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.

Examination of reproductive aging milestones among women who carry the FMR1 premutation

BACKGROUND

The fragile X premutation is characterized by a large CGG repeat track (55-199 repeats) in the 5' UTR of the FMR1 gene. This X-linked mutation leads to an increased risk for premature ovarian failure; interestingly, the association of repeat size with risk is non-linear. We hypothesize that the premutation-associated ovarian insufficiency is due to a diminished oocyte pool and examined reproductive aging milestones by repeat size group to determine if the same non-linear association is observed.

METHODS

We analyzed cross-sectional reproductive history questionnaire data from 948 women with a wide range of repeat sizes.

RESULTS

We have confirmed the non-linear relationship among premutation carriers for ovarian insufficiency. The mid-range repeat size group (80-100 repeats), not the highest group, had an increased risk for: altered cycle traits (shortened cycle length, irregular cycles and skipped cycles), subfertility and dizygotic twinning. Smoking, a modifiable risk, decreased the reproductive lifespan of women with the premutation by about 1 year, similar to its effect on non-carriers. As expected, premutation carriers were found to be at an increased risk for osteoporosis.

CONCLUSIONS

Possible molecular mechanisms to explain the non-linear repeat size risk for ovarian insufficiency are discussed.

Fragile-X syndrome and fragile X-associated tremor/ataxia syndrome: two faces of FMR1

Recent advances in our understanding of the clinical and molecular features of the fragile-X mental-retardation 1 gene, FMR1, highlight the importance of single-gene disorders. 15 years after its discovery, FMR1 continues to reveal new and unexpected clinical presentations and molecular mechanisms. Loss of function of FMR1 is a model for neurodevelopmental and behavioural disorders, including mental retardation, autism, anxiety, and mood instability. In addition, overexpression and CNS toxicity of FMR1 mRNA causes a late-onset neurodegenerative disorder, the fragile-X-associated tremor/ataxia syndrome (FXTAS). A similar mechanism is probably involved in premature ovarian failure, which affects up to 20% of female carriers of an altered FMR1 gene.

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.

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.

Acceptance of fragile X premutation genetic screening in women with ovarian dysfunction

OBJECTIVE

The purpose of this study was to assess patient perception of fragile X premutation genetic testing (FRAX).

STUDY DESIGN

This was a cross-sectional survey of women with elevated follicle stimulating hormone levels with (premature ovarian failure or early menopause [POF/EM], n = 20) or without (diminished ovarian reserve [DOR], n = 20) amenorrhea. Seventy-five percent participated.

RESULTS

Seventy-five percent of the DOR group and 43% of the POF/EM group desired FRAX testing. Eighty-three percent wanted to assist the scientific knowledge of FRAX, even if they did not want to know their own results. POF/EM women were more concerned than DOR women about paying out-of-pocket (P = .001) and maintaining confidentiality insurance-wise (P = .07). Primary motivations for women who wanted testing were the desire to know if they have FRAX, and wanting to determine if FRAX is the cause of their ovarian dysfunction. The primary decision factor for those declining testing was unwillingness to pay out-of-pocket (75%).

CONCLUSION

Women with ovarian dysfunction are interested in FRAX testing. Cost, confidentiality, and the implications for relatives are their key concerns.

Mosaicism for anFMR1 gene deletion in a fragile X female

Most cases of fragile X syndrome result from expansion of CGG repeats in the FMR1 gene; deletions and point mutations of FMR1 are much less common. Mosaicism for an FMR1 full mutation with a deletion or with a normal allele has been reported in fragile X males. Here we report on a fragile X female who is mosaic for an FMR1 full mutation and an intragenic deletion. The patient is a 4-year-old girl with developmental delay, autistic-like behaviors, and significant speech and language abnormalities. Southern blotting demonstrated the presence of a methylated full mutation, a normal allele in methylated and unmethylated forms, and an additional fragment smaller than the normal methylated allele. This result indicates that the patient is mosaic for a full mutation and a deletion, in the presence of a normal allele. By DNA sequence analysis, we mapped the 5' breakpoint 63/65 bp upstream from the CGG repeat region and the 3' breakpoint 86/88 bp downstream of the CGG repeats within the FMR1 gene. The deletion removed 210 bp, including the entire CGG repeat region. The full mutation was inherited from a premutation in the patient's mother. The deletion, which remained methylated at the Eag I and Nru I sites, was probably derived from the full mutation allele. Mosaicism of this type is rare in females with a fragile X mutation but should be kept in mind in the interpretation of Southern blots.