A genome-wide association study of early menopause and the combined impact of identified variants

Interindividual variation in ovarian reserve after gonadotoxic treatment in female childhood cancer survivors - a genome-wide association study: results from PanCareLIFE

OBJECTIVE

To discover new variants associated with low ovarian reserve after gonadotoxic treatment among adult female childhood cancer survivors using a genome-wide association study approach.

DESIGN

Genome-wide association study.

SETTING

Not applicable.

PATIENTS

A discovery cohort of adult female childhood cancer survivors from the pan-European PanCareLIFE cohort (n = 743; median age: 25.8 years), excluding those who received bilateral ovarian irradiation, bilateral oophorectomy, central nervous system or total body irradiation, or stem cell transplantation. Replication was attempted in the US-based St. Jude Lifetime Cohort (n = 391; median age: 31.3 years).

EXPOSURE

Female childhood cancer survivors are at risk of therapy-related gonadal impairment. Alkylating agents are well-established risk factors, and the interindividual variability in gonadotoxicity may be explained by genetic polymorphisms. Data were collected in real-life conditions, and cyclophosphamide equivalent doses were used to quantify alkylation agent exposure.

MAIN OUTCOME MEASURE

Anti-Müllerian hormone (AMH) levels served as a proxy for ovarian function, and the findings were combined in a meta-analysis.

RESULTS

Three genome-wide significant (<5.0 × 10-8) and 16 genome-wide suggestive (<5.0 × 10-6) loci were associated with log-transformed AMH levels, adjusted for cyclophosphamide equivalent dose of alkylating agents, age at diagnosis, and age at study in the PanCareLIFE cohort. On the basis of the effect allele frequency (EAF) (>0.01 if not genome-wide significant), and biologic relevance, 15 single nucleotide polymorphisms were selected for replication. None of the single nucleotide polymorphisms were statistically significantly associated with AMH levels. A meta-analysis indicated that rs78861946 was associated with borderline genome-wide statistical significance (reference/effect allele: C/T; effect allele frequency: 0.04, beta (SE): -0.484 (0.091).

CONCLUSION

This study found no genetic variants associated with a lower ovarian reserve after gonadotoxic treatment because the findings of this genome-wide association study were not statistically significant replicated in the replication cohort. Suggestive evidence for the potential importance of 1 variant is briefly discussed, but the lack of statistical significance calls for larger cohort sizes. Because the population of childhood cancer survivors is increasing, large-scale and systematic research is needed to identify genetic variants that could aid predictive risk models of gonadotoxicity as well as fertility preservation options for childhood cancer survivors.

Homozygosity for a stop-gain variant in CCDC201 causes primary ovarian insufficiency

Age at menopause (AOM) has a substantial impact on fertility and disease risk. While many loci with variants that associate with AOM have been identified through genome-wide association studies (GWAS) under an additive model, other genetic models are rarely considered1. Here through GWAS meta-analysis under the recessive model of 174,329 postmenopausal women from Iceland, Denmark, the United Kingdom (UK; UK Biobank) and Norway, we study low-frequency variants with a large effect on AOM. We discovered that women homozygous for the stop-gain variant rs117316434 (A) in CCDC201 (p.(Arg162Ter), minor allele frequency ~1%) reached menopause 9 years earlier than other women (P = 1.3 × 10-15). The genotype is present in one in 10,000 northern European women and leads to primary ovarian insufficiency in close to half of them. Consequently, homozygotes have fewer children, and the age at last childbirth is 5 years earlier (P = 3.8 × 10-5). The CCDC201 gene was only found in humans in 2022 and is highly expressed in oocytes. Homozygosity for CCDC201 loss-of-function has a substantial impact on female reproductive health, and homozygotes would benefit from reproductive counseling and treatment for symptoms of early menopause.

Genetic links between ovarian ageing, cancer risk and de novo mutation rates

Human genetic studies of common variants have provided substantial insight into the biological mechanisms that govern ovarian ageing1. Here we report analyses of rare protein-coding variants in 106,973 women from the UK Biobank study, implicating genes with effects around five times larger than previously found for common variants (ETAA1, ZNF518A, PNPLA8, PALB2 and SAMHD1). The SAMHD1 association reinforces the link between ovarian ageing and cancer susceptibility1, with damaging germline variants being associated with extended reproductive lifespan and increased all-cause cancer risk in both men and women. Protein-truncating variants in ZNF518A are associated with shorter reproductive lifespan-that is, earlier age at menopause (by 5.61 years) and later age at menarche (by 0.56 years). Finally, using 8,089 sequenced trios from the 100,000 Genomes Project (100kGP), we observe that common genetic variants associated with earlier ovarian ageing associate with an increased rate of maternally derived de novo mutations. Although we were unable to replicate the finding in independent samples from the deCODE study, it is consistent with the expected role of DNA damage response genes in maintaining the genetic integrity of germ cells. This study provides evidence of genetic links between age of menopause and cancer risk.

Pharmacogenomic studies of fertility outcomes in pediatric cancer survivors - A systematic review

For the same age, sex, and dosage, there can be significant variation in fertility outcomes in childhood cancer survivors. Genetics may explain this variation. This study aims to: (i) review the genetic contributions to infertility, (ii) search for pharmacogenomic studies looking at interactions of cancer treatment, genetic predisposition and fertility-related outcomes. Systematic searches in MEDLINE Ovid, Embase Classic+Embase, and PubMed were conducted using the following selection criteria: (i) pediatric, adolescent, and young adult cancer survivors, below 25 years old at the time of diagnosis, (ii) fertility outcome measures after cancer therapy, (iii) genetic considerations. Studies were excluded if they were (i) conducted in animal models, (ii) were not published in English, (iii) editorial letters, (iv) theses. Articles were screened in Covidence by at least two independent reviewers, followed by data extraction and a risk of bias assessment using the Quality in Prognostic Studies tool. Eight articles were reviewed with a total of 29 genes. Outcome measures included sperm concentration, azoospermia, AMH levels, assessment of premature menopause, ever being pregnant or siring a pregnancy. Three studies included replication cohorts, which attempted replication of SNP findings for NPY2R, BRSK1, FANCI, CYP2C19, CYP3A4, and CYP2B6. Six studies were rated with a high risk of bias. Differing methods may explain a lack of replication, and small cohorts may have contributed to few significant findings. Larger, prospective longitudinal studies with an unbiased genome-wide focus will be important to replicate significant results, which can be applied clinically.

Novel compound heterozygous variants in FANCI cause premature ovarian insufficiency

Premature ovarian insufficiency (POI) is a common reproductive aging disorder due to a dramatic decline of ovarian function before 40 years of age. Accumulating evidence reveals that genetic defects, particularly those related to DNA damage response, are a crucial contributing factor to POI. We have demonstrated that the functional Fanconi anemia (FA) pathway maintains the rapid proliferation of primordial germ cells to establish a sufficient reproductive reserve by counteracting replication stress, but the clinical implications of this function in human ovarian function remain to be established. Here, we screened the FANCI gene, which encodes a key component for FA pathway activation, in our whole-exome sequencing database of 1030 patients with idiopathic POI, and identified two pairs of novel compound heterozygous variants, c.[97C > T];[1865C > T] and c.[158-2A > G];[c.959A > G], in two POI patients, respectively. The missense variants did not alter FANCI protein expression and nuclear localization, apart from the variant c.158-2A > G causing abnormal splicing and leading to a truncated mutant p.(S54Pfs*5). Furthermore, the four variants all diminished FANCD2 ubiquitination levels and increased DNA damage under replication stress, suggesting that the FANCI variants impaired FA pathway activation and replication stress response. This study first links replication stress response defects with the pathogenesis of human POI, providing a new insight into the essential roles of the FA genes in ovarian function.

Micronutrients intake and genetic variants associated with premature ovarian insufficiency; MASHAD cohort study

BACKGROUND AND AIM

premature ovarian insufficiency (POI) is defined as the menopause before 40 years of age, and its prevalence is reported to be two-fold higher in Iranian women than the average for woman globally. POI is associated with several cardio/cerebrovascular complications as well as an increased overall mortality. Genetic factors, and serum levels of minerals and vitamin D, have been reported to be related to the prevalence of POI. We have investigated the association between some POI -related genotypes with the serum levels of some important micronutrients.

METHODS

One hundred and seventeen women with POI and 183 controls without any renal, hepatic, and thyroid abnormalities were recruited as part of the MASHAD study. Demographic and anthropometric features were recorded and blood samples were collected and processed. DNA was extracted from the buffy coat of blood samples from all participants and 8 POI-related single nucleotide polymorphisms (SNPs) were determined using ASO-PCR or Tetra ARMS-PCR. Serum minerals and vitamin D concentrations were measured using routine methods.

RESULTS

In women with POI, serum copper, phosphate, and calcium were significantly different for those with rs244715, rs16991615, and rs4806660 genotypes, respectively. In our control population, significant differences were also found in serum copper concentrations between different genotypes of rs4806660, rs7246479, rs1046089, and rs2303369. After adjusting for all confounding factors, the women with POI carrying TC genotype (rs4806660) had a lower risk to have serum copper levels < 80 (µg/dL) than those carrying a TT genotype. Furthermore, women with POI carrying GG genotype (rs244715) had a 6-fold higher risk to have serum copper levels > 155 than those carrying AA genotype.

CONCLUSION

The C and G alleles of the rs4806660 and rs244715 polymorphisms respectively are independently associated with serum copper in women with POI. Further studies are necessary to investigate the association of serum copper and other micronutrients in women and other POI -related polymorphisms.

Association between Genetic Variants Linked to Premature Ovarian Insufficiency and Inflammatory Markers: A Cross-Sectional Study

BACKGROUND

Premature menopause (PM) is the cessation of ovarian function before age 40. PM women are more likely to have cardiovascular diseases (CVDs), diabetes, and mental disorders. This is the first study that assessed the association of single nucleotide polymorphisms (SNPs) with anti-heat shock protein 27 (Hsp27), High-sensitivity C-reactive protein (hs- CRP), and PM and serum pro-oxidant-antioxidant balance (PAB), as putative risk factors for CVDs. We aimed to explore the association of oxidative stress markers with eight different SNPs shown to be related to premature menopause.

MATERIALS AND METHODS

In this cross-sectional research, we included 183 healthy women and 117 premature menopausal women. We determined baseline characteristics for all participants and measured serum hs-CRP, anti-HSP-27 antibody titer, and PAB levels using the established methods. Genotyping for eight SNPs was done using the tetra amplification refractory mutation system polymerase chain reaction (Tetra-ARMS PCR) and allele-specific oligonucleotide PCR (ASO-PCR) methods.

RESULTS

We found a significant difference between mean serum PAB levels and the genetic variant of rs16991615 (P=0.03). ANCOVA showed a significant effect of the genotypes rs4806660 and rs10183486 on hs-CRP serum levels in the case and control groups, respectively (P=0.04 and P=0.007). ANCOVA also showed an association between rs244715 genotypes and anti-hsp27 serum levels in the case group (P=0.02). There was a significant effect of the genotypes of rs451417 on the serum hs-CRP level in the control group (P=0.03).

CONCLUSION

There was a significant association of the genetic variants related to PM with oxidative stress and inflammatory markers (serum PAB, anti-hsp27 antibody, and hs-CRP). Accordingly, this seems to be an effective approach to predicting susceptible subjects for cardiovascular and mental disorders as well as various cancers.

The relationship of maternal polymorphisms of genes related to meiosis and DNA damage repair with fetal chromosomal stability

OBJECTIVES

To evaluate the association between maternal polymorphisms of NANOS3 rs2016163, HELQ rs4693089, PRIM1 rs2277339, TLK1 rs10183486, ERCC6 rs2228526, EXO1 rs1635501, DMC1 rs5757133, and MSH5 rs2075789 and fetal chromosomal abnormality.

METHODS

This retrospective case-control study included 571 women with fetal chromosome abnormalities (330 pregnant women diagnosed with fetal aneuploidy, 241 with fetal de novo structural chromosome pregnancy) and 811 healthy pregnant women between January 2018 and April 2022. All the above polymorphisms were tested using SNaPshot.

RESULTS

All the eight polymorphisms were analyzed for genotypes, alleles, under dominant and recessive genetic models. Significant distribution differences of TLK1 rs10183486 in fetal chromosome structural abnormality were found between the case group and control subjects who were <35 years of age [Genotype: p=0.029; Dominant: OR (95 %CI)=0.46 (0.25-0.82), p=0.01 and allele: OR (95 %CI)=0.47 (0.27-0.82), p=0.01 respectively], while no difference was found in the recessive model [OR (95 %CI)=2.49 (0.31-20.40), p=0.39]. In advanced age subgroups for fetal aneuploidy, significant differences were found in genotypes analysis of PRIM1 rs2277339 (p=0.008), allele analysis of TLK1 rs10183486 [OR (95 %CI)=0.62 (0.42-0.91), p=0.02]. For the fetal chromosome structural abnormality population, HELQ rs4693089 revealed a significant distribution difference (p=0.01) but not in the allele, dominant and recessive genetic models analysis (p>0.05 individually).

CONCLUSIONS

For older women, maternal PRIM1 rs2277339 and TLK1 rs10183486 polymorphisms may be associated with fetal aneuploidy, while HELQ rs4693089 may be associated with fetal chromosome structural abnormality. Also, carriers of T allele of TLK1 rs10183486 have a lower risk of fetal chromosome structural abnormality in younger women.

Review of mendelian randomization studies on age at natural menopause

Menopause marks the end of the reproductive phase of life. Based on epidemiological studies, abnormal age at natural menopause (ANM) is thought to contribute to a number of adverse outcomes, such as osteoporosis, cardiovascular disease, and cancer. However, the causality of these associations remains unclear. A powerful epidemiological method known as Mendelian randomization (MR) can be used to clarify the causality between ANM and other diseases or traits. The present review describes MR studies that included ANM as an exposure, outcome and mediator. The findings of MR analyses on ANM have revealed that higher body mass index, poor educational level, early age at menarche, early age at first live birth, early age at first sexual intercourse, and autoimmune thyroid disease appear to be involved in early ANM etiology. The etiology of late ANM appears to be influenced by higher free thyroxine 4 and methylene tetrahydrofolate reductase gene mutations. Furthermore, early ANM has been found to be causally associated with an increased risk of osteoporosis, fracture, type 2 diabetes mellitus, glycosylated hemoglobin, and the homeostasis model of insulin resistance level. In addition, late ANM has been found to be causally associated with an increased systolic blood pressure, higher risk of breast cancer, endometrial cancer, endometrioid ovarian carcinoma, lung cancer, longevity, airflow obstruction, and lower risk of Parkinson's disease. ANM is also a mediator for breast cancer caused by birth weight and childhood body size. However, due to the different instrumental variables used, some results of studies are inconsistent. Future studies with more valid genetic variants are needed for traits with discrepancies between MRs or between MR and other types of epidemiological studies.

Penetrance of pathogenic genetic variants associated with premature ovarian insufficiency

Premature ovarian insufficiency (POI) affects 1% of women and is a leading cause of infertility. It is often considered to be a monogenic disorder, with pathogenic variants in ~100 genes described in the literature. We sought to systematically evaluate the penetrance of variants in these genes using exome sequence data in 104,733 women from the UK Biobank, 2,231 (1.14%) of whom reported at natural menopause under the age of 40 years. We found limited evidence to support any previously reported autosomal dominant effect. For nearly all heterozygous effects on previously reported POI genes, we ruled out even modest penetrance, with 99.9% (13,699 out of 13,708) of all protein-truncating variants found in reproductively healthy women. We found evidence of haploinsufficiency effects in several genes, including TWNK (1.54 years earlier menopause, P = 1.59 × 10-6) and SOHLH2 (3.48 years earlier menopause, P = 1.03 × 10-4). Collectively, our results suggest that, for the vast majority of women, POI is not caused by autosomal dominant variants either in genes previously reported or currently evaluated in clinical diagnostic panels. Our findings, plus previous studies, suggest that most POI cases are likely oligogenic or polygenic in nature, which has important implications for future clinical genetic studies, and genetic counseling for families affected by POI.

Progress in genome-wide association studies of age at natural menopause

Menopause is not only the end of reproductive life, it is also related to diseases such as hyperlipidaemia, atherosclerotic cardiovascular disease, osteoporosis and breast cancer. Traditional epidemiological studies have found that heredity is the main determinant of age at natural menopause (ANM). Early studies on genetic factors were limited to candidate gene studies. Menopause age is not inherited by a single gene, but is the result of multiple gene effects. With the development of genomic technology, the Reproductive Genetics Consortium conducted several genome-wide association studies on ANM in people of European descent, and found that defects in DNA damage repair pathways were the main genetic mechanism. In recent years, due to the ethnic heterogeneity of ANM, there has been further development of global studies into multi-ethnic and trans-ethnic genome-wide association studies. Further genetic and epidemiological studies, including polygenetic score and genetic mechanism research, should be conducted to investigate the pathogenesis and mechanism with respect to menopause and its related diseases.

Selected Genetic Factors Associated with Primary Ovarian Insufficiency

Primary ovarian insufficiency (POI) is a heterogeneous disease resulting from non-functional ovaries in women before the age of 40. It is characterized by primary amenorrhea or secondary amenorrhea. As regards its etiology, although many POI cases are idiopathic, menopausal age is a heritable trait and genetic factors play an important role in all POI cases with known causes, accounting for approximately 20% to 25% of cases. This paper reviews the selected genetic causes implicated in POI and examines their pathogenic mechanisms to show the crucial role of genetic effects on POI. The genetic factors that can be found in POI cases include chromosomal abnormalities (e.g., X chromosomal aneuploidies, structural X chromosomal abnormalities, X-autosome translocations, and autosomal variations), single gene mutations (e.g., newborn ovary homeobox gene (NOBOX), folliculogenesis specific bHLH transcription factor (FIGLA), follicle-stimulating hormone receptor (FSHR), forkhead box L2 (FOXL2), bone morphogenetic protein 15 (BMP15), etc., as well as defects in mitochondrial functions and non-coding RNAs (small ncRNAs and long ncRNAs). These findings are beneficial for doctors to diagnose idiopathic POI cases and predict the risk of POI in women.

Multi-omics and machine learning for the prevention and management of female reproductive health

Females typically carry most of the burden of reproduction in mammals. In humans, this burden is exacerbated further, as the evolutionary advantage of a large and complex human brain came at a great cost of women's reproductive health. Pregnancy thus became a highly demanding phase in a woman's life cycle both physically and emotionally and therefore needs monitoring to assure an optimal outcome. Moreover, an increasing societal trend towards reproductive complications partly due to the increasing maternal age and global obesity pandemic demands closer monitoring of female reproductive health. This review first provides an overview of female reproductive biology and further explores utilization of large-scale data analysis and -omics techniques (genomics, transcriptomics, proteomics, and metabolomics) towards diagnosis, prognosis, and management of female reproductive disorders. In addition, we explore machine learning approaches for predictive models towards prevention and management. Furthermore, mobile apps and wearable devices provide a promise of continuous monitoring of health. These complementary technologies can be combined towards monitoring female (fertility-related) health and detection of any early complications to provide intervention solutions. In summary, technological advances (e.g., omics and wearables) have shown a promise towards diagnosis, prognosis, and management of female reproductive disorders. Systematic integration of these technologies is needed urgently in female reproductive healthcare to be further implemented in the national healthcare systems for societal benefit.

Ovarian Reserve Disorders, Can We Prevent Them? A Review

The ovarian reserve is finite and begins declining from its peak at mid-gestation until only residual follicles remain as women approach menopause. Reduced ovarian reserve, or its extreme form, premature ovarian insufficiency, stems from multiple factors, including developmental, genetic, environmental exposures, autoimmune disease, or medical/surgical treatment. In many cases, the cause remains unknown and resulting infertility is not ultimately addressed by assisted reproductive technologies. Deciphering the mechanisms that underlie disorders of ovarian reserve could improve the outcomes for patients struggling with infertility, but these disorders are diverse and can be categorized in multiple ways. In this review, we will explore the topic from a perspective that emphasizes the prevention or mitigation of ovarian damage. The most desirable mode of fertoprotection is primary prevention (intervening before ablative influence occurs), as identifying toxic influences and deciphering the mechanisms by which they exert their effect can reduce or eliminate exposure and damage. Secondary prevention in the form of screening is not recommended broadly. Nevertheless, in some instances where a known genetic background exists in discrete families, screening is advised. As part of prenatal care, screening panels include some genetic diseases that can lead to infertility or subfertility. In these patients, early diagnosis could enable fertility preservation or changes in family-building plans. Finally, Tertiary Prevention (managing disease post-diagnosis) is critical. Reduced ovarian reserve has a major influence on physiology beyond fertility, including delayed/absent puberty or premature menopause. In these instances, proper diagnosis and medical therapy can reduce adverse effects. Here, we elaborate on these modes of prevention as well as proposed mechanisms that underlie ovarian reserve disorders.

Genetically Determined Reproductive Aging and Coronary Heart Disease: A Bidirectional 2-sample Mendelian Randomization

BACKGROUND

Accelerated reproductive aging, in women indicated by early natural menopause, is associated with increased coronary heart disease (CHD) risk in observational studies. Conversely, an adverse CHD risk profile has been suggested to accelerate menopause.

OBJECTIVES

To study the direction and evidence for causality of the relationship between reproductive aging and (non-)fatal CHD and CHD risk factors in a bidirectional Mendelian randomization (MR) approach, using age at natural menopause (ANM) genetic variants as a measure for genetically determined reproductive aging in women. We also studied the association of these variants with CHD risk (factors) in men.

DESIGN

Two-sample MR, using both cohort data as well as summary statistics, with 4 methods: simple and weighted median-based, standard inverse-variance weighted (IVW) regression, and MR-Egger regression.

PARTICIPANTS

Data from EPIC-CVD and summary statistics from UK Biobank and publicly available genome-wide association studies were pooled for the different analyses.

MAIN OUTCOME MEASURES

CHD, CHD risk factors, and ANM.

RESULTS

Across different methods of MR, no association was found between genetically determined reproductive aging and CHD risk in women (relative risk estimateIVW = 0.99; 95% confidence interval (CI), 0.97-1.01), or any of the CHD risk factors. Similarly, no associations were found in men. Neither did the reversed analyses show evidence for an association between CHD (risk factors) and reproductive aging.

CONCLUSION

Genetically determined reproductive aging is not causally associated with CHD risk (factors) in women, nor were the genetic variants associated in men. We found no evidence for a reverse association in a combined sample of women and men.

Rare coding variants in DNA damage repair genes associated with timing of natural menopause

The age of menopause is associated with fertility and disease risk, and its genetic control is of great interest. We use whole-exome sequences from 132,370 women in the UK Biobank to test for associations between rare damaging variants and age at natural menopause. Rare damaging variants in five genes are significantly associated with menopause: CHEK2 (p = 3.3 × 10⁻⁵¹), DCLRE1A (p = 8.4 × 10⁻¹³), and HELB (p = 5.7 × 10⁻⁷) with later menopause and TOP3A (p = 7.6 × 10⁻⁸) and CLPB (p = 8.1 × 10⁻⁷) with earlier menopause. Two additional genes are suggestive: RAD54L (p = 2.4 × 10⁻⁶) with later menopause and HROB (p = 2.9 × 10⁻⁶) with earlier menopause. In a follow-up analysis of repeated questionnaires in women who were initially premenopausal, CHEK2, TOP3A, and RAD54L genotypes are associated with subsequent menopause. Consistent with previous genome-wide association studies (GWASs), six of the seven genes are involved in the DNA damage repair pathway. Phenome-wide scans across 398,569 men and women revealed that in addition to known associations with cancers and blood cell counts, rare variants in CHEK2 are also associated with increased risk for uterine fibroids, polycystic ovary syndrome, and prostate hypertrophy; these associations are not shared with higher-penetrance breast cancer genes. Causal mediation analysis suggests that approximately 8% of the breast cancer risk conferred by CHEK2 pathogenic variants after menopause is mediated through delayed menopause.

White paper: Onco-fertility in pediatric patients with Wilms tumor

The survival of childhood Wilms tumor is currently around 90%, with many survivors reaching reproductive age. Chemotherapy and radiotherapy are established risk factors for gonadal damage and are used in both COG and SIOP Wilms tumor treatment protocols. The risk of infertility in Wilms tumor patients is low but increases with intensification of treatment including the use of alkylating agents, whole abdominal radiation or radiotherapy to the pelvis. Both COG and SIOP protocols aim to limit the use of gonadotoxic treatment, but unfortunately this cannot be avoided in all patients. Infertility is considered one of the most important late effects of childhood cancer treatment by patients and their families. Thus, timely discussion of gonadal damage risk and fertility preservation options is important. Additionally, irrespective of the choice for preservation, consultation with a fertility preservation (FP) team is associated with decreased patient and family regret and better quality of life. Current guidelines recommend early discussion of the impact of therapy on potential fertility. Since most patients with Wilms tumors are prepubertal, potential FP methods for this group are still considered experimental. There are no proven methods for FP for prepubertal males (testicular biopsy for cryopreservation is experimental), and there is just a single option for prepubertal females (ovarian tissue cryopreservation), posing both technical and ethical challenges. Identification of genetic markers of susceptibility to gonadotoxic therapy may help to stratify patient risk of gonadal damage and identify patients most likely to benefit from FP methods.

Obesity and risk of female reproductive conditions: A Mendelian randomisation study

BACKGROUND

Obesity is observationally associated with altered risk of many female reproductive conditions. These include polycystic ovary syndrome (PCOS), abnormal uterine bleeding, endometriosis, infertility, and pregnancy-related disorders. However, the roles and mechanisms of obesity in the aetiology of reproductive disorders remain unclear. Thus, we aimed to estimate observational and genetically predicted causal associations between obesity, metabolic hormones, and female reproductive disorders.

METHODS AND FINDINGS

Logistic regression, generalised additive models, and Mendelian randomisation (MR) (2-sample, non-linear, and multivariable) were applied to obesity and reproductive disease data on up to 257,193 women of European ancestry in UK Biobank and publicly available genome-wide association studies (GWASs). Body mass index (BMI), waist-to-hip ratio (WHR), and WHR adjusted for BMI were observationally (odds ratios [ORs] = 1.02-1.87 per 1-SD increase in obesity trait) and genetically (ORs = 1.06-2.09) associated with uterine fibroids (UF), PCOS, heavy menstrual bleeding (HMB), and pre-eclampsia. Genetically predicted visceral adipose tissue (VAT) mass was associated with the development of HMB (OR [95% CI] per 1-kg increase in predicted VAT mass = 1.32 [1.06-1.64], P = 0.0130), PCOS (OR [95% CI] = 1.15 [1.08-1.23], P = 3.24 × 10-05), and pre-eclampsia (OR [95% CI] = 3.08 [1.98-4.79], P = 6.65 × 10-07). Increased waist circumference posed a higher genetic risk (ORs = 1.16-1.93) for the development of these disorders and UF than did increased hip circumference (ORs = 1.06-1.10). Leptin, fasting insulin, and insulin resistance each mediated between 20% and 50% of the total genetically predicted association of obesity with pre-eclampsia. Reproductive conditions clustered based on shared genetic components of their aetiological relationships with obesity. This study was limited in power by the low prevalence of female reproductive conditions among women in the UK Biobank, with little information on pre-diagnostic anthropometric traits, and by the susceptibility of MR estimates to genetic pleiotropy.

CONCLUSIONS

We found that common indices of overall and central obesity were associated with increased risks of reproductive disorders to heterogenous extents in a systematic, large-scale genetics-based analysis of the aetiological relationships between obesity and female reproductive conditions. Our results suggest the utility of exploring the mechanisms mediating the causal associations of overweight and obesity with gynaecological health to identify targets for disease prevention and treatment.

Nrf2 Signaling Pathway Mediates the Protective Effects of Daphnetin Against D-Galactose Induced-Premature Ovarian Failure

Oxidative damage can lead to severe ovarian dysfunctions and even premature ovarian failure. Nrf2, a significant transcription factor that regulates the oxidative stress response of cells, declines with age. Daphnetin, as a kind of natural Chinese herbal medicine, can activate Nrf2 and further promote the antioxidant defense of cells. However, whether Daphnetin treatment can protect ovary from premature ovarian failure and the specific mechanism involved are not understood. This study aimed to investigate the protective function of Daphnetin against the ovarian aging induced by D-galactose in wild-type and Nrf2^−/− mice. Female C57BL/6 mice with Wild-type and Nrf2^−/− were divided into five groups separately and the premature ovarian failure model were established by D-galactose and then Daphnetin and VE were given for treatment. After 42 days, ovaries tissue and serum were collected for biochemical determination, H&E staining, Immunohistochemical staining and western blot analysis. In the WT-POF group, ovarian function was broke, and the expression of the ovarian senescence-associated protein P16 and the level of oxidative stress were significantly increased, while the expression of the anti-senescence protein klotho was significantly decreased. In addition, the expression of Nrf2 and the antioxidases GCLC, HO-1 and NQO1 were decreased, but TXNIP and NLRP3 were significantly increased. Furthermore, the characteristics of premature ovarian failure were more significant in Nrf2 knockout mice than in wild-type mice, especially the expression of NLRP3 and TXNIP. Moreover, daphnetin, an Nrf2 activator, rescued d-gal-induced POF in a dose-dependent manner, while the protective effect was weakened or even lost in Nrf2 knockout mice. Our results suggested that daphnetin is likely to be a candidate drug for premature ovarian failure treatment and it is mostly possible referred to the molecular mechanism of increasing Nrf2 expression and inhibiting NLRP3 activation in the ovarian aging process.

Shared Genetics Between Age at Menopause, Early Menopause, POI and Other Traits

Reproductive ageing leading to menopause is characterized by depletion of follicles and its regulating mechanisms are only partly understood. Early age at menopause and premature ovarian insufficiency (POI) are associated with several other traits such as cardiovascular disease, dyslipidemia, osteoporosis and diabetes. In large cohorts of Northern European women hundreds of Single Nucleotide Polymorphisms (SNPs) have been identified to be associated with age at menopause. These SNPs are located in genes enriched for immune and mitochondrial function as well as DNA repair and maintenance processes. Genetic predisposition to earlier menopause might also increase the risk of other associated traits. Increased risk for cardiovascular disease in women has been associated with age at menopause lowering SNPs. Pleiotropy between early age at menopause and increased mortality from coronary artery disease has been observed, implicating that genetic variants affecting age at menopause also affect the risk for coronary deaths. This review will discuss the shared genetics of age at menopause with other traits. Mendelian Randomization studies implicate causal genetic association between age at menopause and age at menarche, breast cancer, ovarian cancer, BMD and type 2 diabetes. Although the shared biological pathways remain to be determined, mechanisms that regulate duration of estrogen exposure remain an important focus.

Prenatal exposure to propylparaben at human-relevant doses accelerates ovarian aging in adult mice

Embryonic exposure to environmental chemicals may result in specific chronic diseases in adulthood. Parabens, a type of environmental endocrine disruptors widely used in pharmaceuticals and cosmetics, have been shown to cause a decline in women's reproductive function. However, whether exposure to parabens during pregnancy also negatively affect the ovarian function of the female offspring in adulthood remains unclear. This study aims to investigate the effects of prenatal propylparaben (PrP) exposure on the ovarian function of adult mice aged 46 weeks, which is equivalent to the age of 40 years in women. Pregnant ICR mice were intraperitoneally injected with human-relevant doses of PrP (i.e., 0, 7.5, 90, and 450 mg/kg/day) during the fetal sex determination period-from embryonic day E7.5 to E13.5. Our results revealed that ovarian aging was accelerated in PrP-exposed mice at 46 weeks, with altered regularity of the estrous cycle, decreased serum estrogen (E2) and progesterone (P4) levels, reduced size of the primordial follicle pool, and increased number of atretic follicles. It was found that prenatal exposure to human-relevant doses of PrP exacerbated ovarian oxidative stress, inflammation, and fibrosis, which promoted follicular atresia by activating the mitochondrial apoptosis pathway. To compensate, the depletion of primordial follicles was also accelerated by activating the PI3K/AKT/mTOR signaling pathway in PrP-exposed mice. Moreover, PrP induced hypermethylation of CpG sites in the promoter region of Cyp11a1 (a 17.16-64.28% increase) partly led to the disrupted steroidogenesis, and the altered methylation levels of imprinted genes H19 and Peg3 may also contribute to the phenotypes observed. These remarkable findings highlight the embryonic origin of ovarian aging and suggest that a reduced use of PrP during pregnancy should be advocated.

Effect of Genetic Variation in CYP450 on Gonadal Impairment in a European Cohort of Female Childhood Cancer Survivors, Based on a Candidate Gene Approach: Results from the PanCareLIFE Study

BACKGROUND

Female childhood cancer survivors (CCSs) carry a risk of therapy-related gonadal dysfunction. Alkylating agents (AA) are well-established risk factors, yet inter-individual variability in ovarian function is observed. Polymorphisms in CYP450 enzymes may explain this variability in AA-induced ovarian damage. We aimed to evaluate associations between previously identified genetic polymorphisms in CYP450 enzymes and AA-related ovarian function among adult CCSs.

METHODS

Anti-Müllerian hormone (AMH) levels served as a proxy for ovarian function in a discovery cohort of adult female CCSs, from the pan-European PanCareLIFE cohort (n = 743; age (years): median 25.8, interquartile range (IQR) 22.1-30.6). Using two additive genetic models in linear and logistic regression, nine genetic variants in three CYP450 enzymes were analyzed in relation to cyclophosphamide equivalent dose (CED) score and their impact on AMH levels. The main model evaluated the effect of the variant on AMH and the interaction model evaluated the modifying effect of the variant on the impact of CED score on log-transformed AMH levels. Results were validated, and meta-analysis performed, using the USA-based St. Jude Lifetime Cohort (n = 391; age (years): median 31.3, IQR 26.6-37.4).

RESULTS

CYP3A4*3 was significantly associated with AMH levels in the discovery and replication cohort. Meta-analysis revealed a significant main deleterious effect (Beta (95% CI): -0.706 (-1.11--0.298), p-value = 7 × 10-4) of CYP3A4*3 (rs4986910) on log-transformed AMH levels. CYP2B6*2 (rs8192709) showed a significant protective interaction effect (Beta (95% CI): 0.527 (0.126-0.928), p-value = 0.01) on log-transformed AMH levels in CCSs receiving more than 8000 mg/m2 CED.

CONCLUSIONS

Female CCSs CYP3A4*3 carriers had significantly lower AMH levels, and CYP2B6*2 may have a protective effect on AMH levels. Identification of risk-contributing variants may improve individualized counselling regarding the treatment-related risk of infertility and fertility preservation options.

A kaleidoscopic view of ovarian genes associated with premature ovarian insufficiency and senescence

Ovarian infertility and subfertility presenting with premature ovarian insufficiency (POI) and diminished ovarian reserve are major issues facing the developed world due to the trend of delaying childbirth. Ovarian senescence and POI represent a continuum of physiological/pathophysiological changes in ovarian follicle functions. Based on advances in whole exome sequencing, evaluation of gene copy variants, together with family-based and genome-wide association studies, we discussed genes responsible for POI and ovarian senescence. We used a gene-centric approach to sort out literature deposited in the Ovarian Kaleidoscope database (http://okdb.appliedbioinfo.net) by sub-categorizing candidate genes as ligand-receptor signaling, meiosis and DNA repair, transcriptional factors, RNA metabolism, enzymes, and others. We discussed individual gene mutations found in POI patients and verification of gene functions in gene-deleted model organisms. Decreased expression of some of the POI genes could be responsible for ovarian senescence, especially those essential for DNA repair, meiosis and mitochondrial functions. We propose to set up a candidate gene panel for targeted sequencing in POI patients together with studies on mitochondria-associated genes in middle-aged subfertile patients.

Machine Learning-Based Approach Highlights the Use of a Genomic Variant Profile for Precision Medicine in Ovarian Failure

Ovarian failure (OF) is a common cause of infertility usually diagnosed as idiopathic, with genetic causes accounting for 10-25% of cases. Whole-exome sequencing (WES) may enable identifying contributing genes and variant profiles to stratify the population into subtypes of OF. This study sought to identify a blood-based gene variant profile using accumulation of rare variants to promote precision medicine in fertility preservation programs. A case-control (n = 118, n = 32, respectively) WES study was performed in which only non-synonymous rare variants <5% minor allele frequency (MAF; in the IGSR) and coverage ≥ 100× were considered. A profile of 66 variants of uncertain significance was used for training an unsupervised machine learning model to separate cases from controls (97.2% sensitivity, 99.2% specificity) and stratify the population into two subtypes of OF (A and B) (93.31% sensitivity, 96.67% specificity). Model testing within the IGSR female population predicted 0.5% of women as subtype A and 2.4% as subtype B. This is the first study linking OF to the accumulation of rare variants and generates a new potential taxonomy supporting application of this approach for precision medicine in fertility preservation.

BRCA 1, 2 mutation and earlier menopause. Could BRCA 1, 2 be used as predictor of menopause?

Many studies have shown that BRCA mutation is not only related to cancer but also to ovarian aging. Studies in both human and mice oocytes have shown that Double-strand breaks (DSBs) accumulate with age. Genome-wide association studies (GWAS) have found 44 genetic loci that are related to variations when a female is about to have menopause. BRCA1 is involved in these 44 loci that are associated with the age of menopause. This review has gathered all results of literature search about the association between BRCA genes and early menopause. The majority of the articles found that women with BRCA mutation have earlier menopause compared to non-carriers. In conclusion, in the near future BRCA1,2 genes could be used as predictive biomarkers of menopause.

Is climacterium by the mid-40s associated with thyroid dysfunction or autoimmunity? A population-based study

OBJECTIVE

We investigated whether more advanced climacteric stage in the mid-40s is associated with thyroid autoimmunity and dysfunction.

METHODS

This cross-sectional cohort study included 2,569 46-year-old women. Thyroid hormone, thyroid peroxidase antibodies, and follicle-stimulating hormone levels were determined. Using menstrual history and follicle-stimulating hormone levels, the participants were divided into climacteric (n = 340) and preclimacteric (n = 2,229) groups. Women diagnosed with premature ovarian insufficiency (menopause by 40 y of age) were excluded. The use of thyroid medication was evaluated from the medication reimbursement register. The prevalence of thyroid medication use, laboratory-based thyroid dysfunction, and thyroid peroxidase antibody positivity was compared between the two groups. The association between climacteric status and thyroid disorders was investigated using a logistic regression model including smoking and thyroid antibody status.

RESULTS

At 46 years old, climacteric women used thyroid medication more often than preclimacteric women (9.1% vs 6.1%; P = 0.04). There was no difference in the prevalence of subclinical or clinical hypothyroidism and hyperthyroidism in nonmedicated participants (5.5% vs 5.0%; P = 0.7) or thyroid peroxidase antibody positivity (14.0% vs 15.0%, P = 0.7). In the regression model, being climacteric (OR = 1.6; 95% CI 1.1-2.3; P = 0.02) and antibody positivity (OR 4.9; 95% CI 3.6-6.6; P < 0.001) were associated with a higher prevalence of thyroid dysfunction.

CONCLUSIONS

More advanced climacteric stage in the mid-40s was slightly associated with thyroid dysfunction but not thyroid autoimmunity.

Possible modification of BRSK1 on the risk of alkylating chemotherapy-related reduced ovarian function

STUDY QUESTION

Do genetic variations in the DNA damage response pathway modify the adverse effect of alkylating agents on ovarian function in female childhood cancer survivors (CCS)?

SUMMARY ANSWER

Female CCS carrying a common BR serine/threonine kinase 1 (BRSK1) gene variant appear to be at 2.5-fold increased odds of reduced ovarian function after treatment with high doses of alkylating chemotherapy.

WHAT IS KNOWN ALREADY

Female CCS show large inter-individual variability in the impact of DNA-damaging alkylating chemotherapy, given as treatment of childhood cancer, on adult ovarian function. Genetic variants in DNA repair genes affecting ovarian function might explain this variability.

STUDY DESIGN, SIZE, DURATION

CCS for the discovery cohort were identified from the Dutch Childhood Oncology Group (DCOG) LATER VEVO-study, a multi-centre retrospective cohort study evaluating fertility, ovarian reserve and risk of premature menopause among adult female 5-year survivors of childhood cancer. Female 5-year CCS, diagnosed with cancer and treated with chemotherapy before the age of 25 years, and aged 18 years or older at time of study were enrolled in the current study. Results from the discovery Dutch DCOG-LATER VEVO cohort (n = 285) were validated in the pan-European PanCareLIFE (n = 465) and the USA-based St. Jude Lifetime Cohort (n = 391).

PARTICIPANTS/MATERIALS, SETTING, METHODS

To evaluate ovarian function, anti-Müllerian hormone (AMH) levels were assessed in both the discovery cohort and the replication cohorts. Using additive genetic models in linear and logistic regression, five genetic variants involved in DNA damage response were analysed in relation to cyclophosphamide equivalent dose (CED) score and their impact on ovarian function. Results were then examined using fixed-effect meta-analysis.

MAIN RESULTS AND THE ROLE OF CHANCE

Meta-analysis across the three independent cohorts showed a significant interaction effect (P = 3.0 × 10-4) between rs11668344 of BRSK1 (allele frequency = 0.34) among CCS treated with high-dose alkylating agents (CED score ≥8000 mg/m2), resulting in a 2.5-fold increased odds of a reduced ovarian function (lowest AMH tertile) for CCS carrying one G allele compared to CCS without this allele (odds ratio genotype AA: 2.01 vs AG: 5.00).

LIMITATIONS, REASONS FOR CAUTION

While low AMH levels can also identify poor responders in assisted reproductive technology, it needs to be emphasized that AMH remains a surrogate marker of ovarian function.

WIDER IMPLICATIONS OF THE FINDINGS

Further research, validating our findings and identifying additional risk-contributing genetic variants, may enable individualized counselling regarding treatment-related risks and necessity of fertility preservation procedures in girls with cancer.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the PanCareLIFE project that has received funding from the European Union's Seventh Framework Programme for research, technological development and demonstration under grant agreement no 602030. In addition, the DCOG-LATER VEVO study was funded by the Dutch Cancer Society (Grant no. VU 2006-3622) and by the Children Cancer Free Foundation (Project no. 20) and the St Jude Lifetime cohort study by NCI U01 CA195547. The authors declare no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

Genetics of Menopause and Primary Ovarian Insufficiency: Time for a Paradigm Shift?

This review summarizes the existing information concerning the genetic background of menopause and primary ovarian insufficiency (POI). There is overwhelming evidence that majority of genes are involved in double-strand break repair, mismatch repair, and base excision repair. The remaining loci were involved in cell energy metabolism and immune response. Gradual (or in case of rapid POI) accumulation of unrepaired DNA damage causes (premature) cell death and cellular senescence. This in turn leads to exhaustion of cell renewal capacity and cellular dysfunction in affected organs and eventually to aging of the entire soma. Similar erosion of the genome occurs within the germ cell line and the ovaries. Subsequently, the systemic "survival" response intentionally suppresses the sex-steroid hormonal output, which in turn may contribute to the onset of menopause. The latter occurs in particular when age-dependent DNA damage accumulation does not cease. Both effects are expected to synergize to promote (premature) ovarian silencing and install (early) menopause. Consequently, aging of the soma seems to be a primary driver for the loss of ovarian function in women. This challenges the current dogma which implies that loss of ovarian function initiates aging of the soma. It is time for a paradigm shift!

Single- and Multimarker Genome-Wide Scans Evidence Novel Genetic Risk Modifiers for Venous Thromboembolism

Previous genome-wide association studies (GWASs) have established several susceptibility genes for venous thromboembolism (VTE) and suggested many others. However, a large proportion of the genetic variance in VTE remains unexplained. Here, we report genome-wide single- and multimarker as well as gene-level associations with VTE in 964 cases and 899 healthy controls of European ancestry. We report 19 loci at the genome-wide level of association (p ≤ 5 × 10^-8). Our results add to the strong support for the association of genetic variants in F5, NME7, ABO, and FGA with VTE, and identify several loci that have not been previously associated with VTE. Altogether, our novel findings suggest that 20 susceptibility genes for VTE were newly discovered by our study. These genes may impact the production and prothrombotic functions of platelets, endothelial cells, and white and red blood cells. Moreover, the majority of these genes have been previously associated with cardiovascular diseases and/or risk factors for VTE. Future studies are warranted to validate our findings and to investigate the shared genetic architecture with susceptibility factors for other cardiovascular diseases impacting VTE risk.

Genetic Determinants of Premature Menopause in A Mashhad Population Cohort

Background

Premature menopause is characterized by amenorrhea before age of 40 years, markedly raised serum luteinizing hormone (LH) level, follicle-stimulating hormone (FSH) level and reduced serum level of estradiol. Genome-wide analysis suggested several loci associated with premature menopause. Here, we aimed to analyze association of variants at the MCM8, FNDC4, PRRC2A, TLK1, ZNF346 and TMEM150B gene loci with premature menopause.

Materials and Methods

In this cross-sectional study, a total of 117 women with premature menopause were compared to 183 healthy women. Anthropometric indices were measured in all participants: height, weight, body mass index (BMI), waist circumference (WC) and wrist circumference. Eight single-nucleotide polymorphisms (SNPs) of the indicated genes (rs16991615, rs244715, rs451417, rs1046089, rs7246479, rs4806660, rs10183486 and rs2303369) were identified from the literature. Genotyping was performed using tetra-ARMS polymerase chain reaction (PCR) and ASO-PCR methods.

Results

T allele of the rs16991615, rs1046089, rs7246479 and rs10183486, C allele of rs244715, rs451417 and rs4806660 as well as TT genotype of rs2303369 were associated with an increased risk of premature menopause, likely causing susceptibility to primary ovarian insufficiency (POI) in comparison with C allele. We also found an association between the rs16991615 SNP with premature menopause. Frequency of the minor allele in cases was increased for all SNPs in comparison with controls. All minor alleles, except for rs2303369, showed a statistically significant increased odds ratio (OR). However, after Bonferroni correction for multiple testing, none of the P values were remained significant.

Conclusion

The selected polymorphisms in MCM8, FNDC4, PRRC2A, TLK1, ZNF346 and TMEM150B genes may potentially affect susceptibility to premature menopause, although replication of the results in larger cohort could clarify this.

Prevalence and Risk Factors of Premature Ovarian Insufficiency/Early Menopause

Premature ovarian insufficiency (POI) and early menopause, defined as loss of ovarian activity prior to 40 years or menopause between the ages of 40 and 45 years, respectively, is associated with significant adverse health impacts. Recent data indicate that the prevalence of POI and early menopause is greater than was previously thought, affecting more than 10% of women. Biopsychosocial risk factors including genetic, autoimmune, reproductive, lifestyle, early-life, social/environmental, and iatrogenic have been associated with POI/early menopause or earlier age at menopause. However, establishing a causal role and the underlying mechanisms remains elusive. Understanding and clarification of these risk factors will facilitate prevention and risk minimization strategies to optimize women's health.

Strategies to Identify Genetic Variants Causing Infertility

Genetic causes are thought to underlie about half of infertility cases, but understanding the genetic bases has been a major challenge. Modern genomics tools allow more sophisticated exploration of genetic causes of infertility through population, family-based, and individual studies. Nevertheless, potential therapies based on genetic diagnostics will be limited until there is certainty regarding the causality of genetic variants identified in an individual. Genome modulation and editing technologies have revolutionized our ability to functionally test such variants, and also provide a potential means for clinical correction of infertility variants. This review addresses strategies being used to identify causative variants of infertility.

TMEM150B is dispensable for oocyte maturation and female fertility in mouse

Premature ovarian insufficiency (POI) refers to severe decline of ovary function in females which usually leads to infertility. It has been reported that the TMEM150B gene is mostly associated with age at natural menopause, early menopause and POI, but its role in female reproduction remains unknown. In this study, we found Tmem150b was highly expressed in mouse oocytes, but its deletion had no obvious effect on meiotic maturation of oocytes indicated by first polar body emission and spindle morphology. There were also no obvious differences in follicle development and corpus luteum formation between knockout and wild type mice. Finally, knockout of Tmem150b did not affect female fertility and sexual hormone levels. In summary, our results suggest that TMEM150B is not essential for female fertility in mice.

Genetics in human reproduction

Approximately 50% of the causes of infertility are of genetic origin. The objective of this study was to analyze the role of genetics in human reproduction by reviewing the main genetic causes of infertility and the use of preimplantation genetic testing in Brazil. This literature review comprised articles in English and Portuguese published on databases PubMed, Scielo, and Bireme from 1990 to 2019. Randomized clinical trials and specialized guidelines were given preference whenever possible. Genetic cause can be traced back to up to 20% of the cases of severe azoospermia or oligozoospermia. Subjects with these conditions are good candidates for genetic screening. In women, genetic causes of infertility (fragile X syndrome, X-trisomy, and Turner's syndrome, some of which diagnosed with karyotyping) culminate with premature ovarian failure. Genetic screening helps advise couples of the risk of experiencing early reproductive capacity loss and of the chances of their offspring carrying genetic disorders. In addition to enhancing the prevention of serious diseases in the offspring of couples at increased risk of genetic diseases, preimplantation genetic screening improves the success rates of assisted reproduction procedures by allowing the selection of euploid embryos for transfer. The interface between genetics and human reproduction has gained significant relevance, but discussions are still needed on which procedures are clinically and ethically acceptable and how they should be regulated.

A Complex Systems Model of Breast Cancer Etiology: The Paradigm II Conceptual Model

BACKGROUND

The etiology of breast cancer is a complex system of interacting factors from multiple domains. New knowledge about breast cancer etiology continues to be produced by the research community, and the communication of this knowledge to other researchers, practitioners, decision makers, and the public is a challenge.

METHODS

We updated the previously published Paradigm model (PMID: 25017248) to create a framework that describes breast cancer etiology in four overlapping domains of biologic, behavioral, environmental, and social determinants. This new Paradigm II conceptual model was part of a larger modeling effort that included input from multiple experts in fields from genetics to sociology, taking a team and transdisciplinary approach to the common problem of describing breast cancer etiology for the population of California women in 2010. Recent literature was reviewed with an emphasis on systematic reviews when available and larger epidemiologic studies when they were not. Environmental chemicals with strong animal data on etiology were also included.

RESULTS

The resulting model illustrates factors with their strength of association and the quality of the available data. The published evidence supporting each relationship is made available herein, and also in an online dynamic model that allows for manipulation of individual factors leading to breast cancer (https://cbcrp.org/causes/).

CONCLUSIONS

The Paradigm II model illustrates known etiologic factors in breast cancer, as well as gaps in knowledge and areas where better quality data are needed.

IMPACT

The Paradigm II model can be a stimulus for further research and for better understanding of breast cancer etiology.

Oral oyster polypeptides protect ovary against d-galactose-induced premature ovarian failure in C57BL/6 mice

BACKGROUND

Oyster polypeptides have various biofunctions, such as anti-cancer and anti-oxidative stress, but whether it has the protective effects to primary ovarian failure (POF) remains poorly understand. To address this issue, daily gavage of oyster polypeptides was performed to investigate their protective effect, basing on d-galactose-induced POF model in C57BL/6 female mice.

RESULTS

Oyster polypeptides restored the irregular estrous cycles and the abnormal serum follicle stimulating hormone (FSH), luteinizing hormone (LH) and progesterone (P) levels as well as the decreased mRNA expression level of Amh that were induced by d-galactose. The follicle development of POF mice was improved by increasing the primordial follicle ratio and decreasing the atretic follicle number after oral administration of oyster polypeptides. Moreover, in the oyster polypeptides treated mice, the total superoxide dismutase (T-SOD) activity was significantly increased, while the malondialdehyde levels were significantly decreased. The mRNA expression levels of stress-related genes (SOD2, SIRT1 and FOXO3a) were remarkably up-regulated after d-galactose induction, but the up-regulation was weakened or disappeared by the gavage of oyster polypeptides. In addition, oyster polypeptides treatment also reduced the apoptosis of the ovarian granulosa cells and down-regulated the mRNA expression levels of apoptosis-related genes (p53 and Bad but not Bcl-2).

CONCLUSION

This study reveals that oyster polypeptides may protect ovary against d-galactose-induced POF by their anti-oxidative stress activity to rescue d-galactose-induced ovarian oxidative damage and therefore to prevent ovarian cells apoptosis, thereby tipping the abnormality trigged by POF to get close to the normal levels. © 2019 Society of Chemical Industry.

Variation analysis of tousled like kinase 1 gene in patients with sporadic premature ovarian insufficiency

Tousled like kinase 1 (TLK1), a member of DNA repair family, participates in the regulation of chromatin assembly and is associated with early menopause and premature ovarian insufficiency (POI) in European women. However, whether the sequence variant in the TLK1 gene was causative for POI is still elusive. Here we performed direct sequencing of the TLK1 gene in 192 patients with sporadic POI. All exons and exon-intron boundaries of TLK1 were amplified and sequenced. Six known single-nucleotide polymorphisms were identified in POI, including rs149844334, rs11553951, rs757600673, rs2277339, rs113416007 and rs17283147. No novel variant was identified, which indicates that sequence variants in the coding region of TLK1 might be uncommon in Chinese women with POI. The role of TLK1 in POI pathogenesis needs to be further explored in larger cohorts from Chinese and other ethnic populations.

Genetic associations with age of menopause in familial longevity

OBJECTIVE

We hypothesize that mechanisms associated with extended reproductive age may overlap with mechanisms for the selection of genetic variants that slow aging and decrease risk for age-related diseases. Therefore, the goal of this analysis is to search for genetic variants associated with delayed age of menopause (AOM) among women in a study of familial longevity.

METHODS

We performed a meta-analysis of genome-wide association studies for AOM in 1,286 women in the Long Life Family Study (LLFS) and 3,151 women in the Health and Retirement Study, and then sought replication in the Framingham Heart Study (FHS). We used Cox proportional hazard regression of AOM to account for censoring, with a robust variance estimator to adjust for within familial relations.

RESULTS

In the meta-analysis, a single nucleotide polymorphism (SNP) previously associated with AOM reached genome-wide significance (rs16991615; HR = 0.74, P = 6.99 × 10). A total of 35 variants reached >10 level of significance and replicated in the FHS and in a 2015 large meta-analysis (ReproGen Consortium). We also identified several novel SNPs associated with AOM including rs3094005: MICB, rs13196892: TXNDC5 | MUTED, rs72774935: SSBP2 | ATG10, rs9447453: COL12A1, rs114298934: FHL2 | NCK2, rs6467223: TNPO3, rs9666274 and rs10766593: NAV2, and rs7281846: HSPA13.

CONCLUSIONS

This work indicates novel associations and replicates known associations between genetic variants and AOM. A number of these associations make sense for their roles in aging.

VIDEO SUMMARY

Supplemental Digital Content 1, http://links.lww.com/MENO/A420.

Age at menopause and lung function: a Mendelian randomisation study

In observational studies, early menopause is associated with lower forced vital capacity (FVC) and a higher risk of spirometric restriction, but not airflow obstruction. It is, however, unclear if this association is causal. We therefore used a Mendelian randomisation (MR) approach, which is not affected by classical confounding, to assess the effect of age at natural menopause on lung function.

We included 94 742 naturally post-menopausal women from the UK Biobank and performed MR analyses on the effect of age at menopause on forced expiratory volume in 1 s (FEV1), FVC, FEV1/FVC, spirometric restriction (FVC<lower limit of normal (LLN)) and airflow obstruction (FEV1/FVC<LLN). We used the inverse variance-weighted method, as well as methods that adjust for pleiotropy, and compared MR with observational analyses.

The MR analyses showed higher FEV1/FVC and a 15% lower risk of airflow obstruction for women with early (<45 years) compared to normal (45–55 years) menopause. Despite some evidence of pleiotropy, the results were consistent when using MR methods robust to pleiotropy. Similar results were found among never- and ever-smokers, while the protective effect seemed less strong in women who had ever used menopause hormone treatment and in overweight women. There was no strong evidence of an association with FVC or spirometric restriction. In observational analyses of the same dataset, early menopause was associated with a pronounced reduction in FVC and a 13% higher risk of spirometric restriction.

Our MR results suggest that early menopause has a protective effect on airflow obstruction. Further studies are warranted to better understand the inconsistency with observational findings, and to investigate the underlying mechanisms and role of female sex hormones.

Climacteric Status at the Age of 46: Impact on Metabolic Outcomes in Population-Based Study

CONTEXT

Menopausal transition is associated with increased cardiovascular risks. Available data on the effect of earlier climacterium on these risks are limited.

OBJECTIVE

To compare cardiovascular risk-associated parameters at the ages of 14, 31, and 46 in relation to climacteric status at the age of 46.

DESIGN, SETTING, AND PARTICIPANTS

A prospective cohort study including 2685 women from the Northern Finland Birth Cohort 1966.

MAIN OUTCOME MEASURES

Follicle-stimulating hormone, body mass index (BMI), waist circumference, waist-to-hip ratio (WHR), blood pressure (BP), body composition, cholesterol levels, testosterone (T) levels, free androgen index (FAI), high-sensitivity C-reactive protein (hs-CRP), and liver enzymes.

RESULTS

Women who were climacteric at the age of 46 had lower BMIs (P = 0.029), T levels (P = 0.018), and FAIs (P = 0.009) at the age of 31. At the age of 46, they had less skeletal muscle (P < 0.001), a higher fat percentage (P = 0.016), higher cholesterol levels [total cholesterol (P < 0.001), low-density lipoprotein cholesterol (P < 0.001), high-density lipoprotein cholesterol (HDL-C; P = 0.022), and triglycerides (P = 0.008)], and higher alanine aminotransferase (P = 0.023) and γ-glutamyltransferase (P < 0.001) levels compared with preclimacteric women. Waist circumference, WHR, BP, and hs-CRP levels did not differ between the groups. Of the climacteric women, 111/381 were using hormone-replacement therapy (HRT). In subanalysis that excluded the HRT users, triglycerides, HDL-C, and body fat percentage did not differ among the groups.

CONCLUSIONS

Earlier climacterium is associated with mainly unfavorable metabolic changes.

BRCA2 deficiency is a potential driver for human primary ovarian insufficiency

Reproductive problem has been one of the top issues for women health worldwide in recent decades. As a typical female disease, primary ovarian insufficiency (POI) results in a loss of ovarian follicles and oocytes that thus destroys women fertility. However, due to the complex of POI etiology and rare resource of human POI oocytes, few biomarkers have been identified in clinics and no effective strategy could be applied to treat POI patients. In the search of possible association between DNA damage and POI by Smart-Seq2 and RT² profiler PCR array, we find that BRCA2, a core DNA repair gene for homologous recombination shows significantly lower expression in two POI patient oocytes. In line with this, we generated oocyte-specific knockout mouse model driven by Gdf9-Cre. The Brca2-deficient mice are infertile because of the arrested follicle development and defective oocyte quality caused by the accumulation of DNA damage. Notably, ectopic expression of Brca2 in Brca2-deficient oocytes could partially restore the oocyte maturation and chromosome stability. Collectively, our data assign a definite deficiency to BRCA2 as a POI driver during follicle development and oocyte maturation, and provide a potential fertility treatment strategy for POI patients induced by BRCA2 deficiency.

A SNP upstream of the cyclic GMP-AMP synthase (cGAS) gene protects from relapse and extra-pulmonary TB and relates to BCG vaccination status in an Indian cohort

Tuberculosis (TB) caused by Mycobacterium tuberculosis (M.tb) is a major health care threat worldwide causing over a million deaths annually. Host-pathogen interaction is complex, and a strong genetic contribution to disease susceptibility has been proposed. We have investigated single-nucleotide polymorphisms (SNPs) within cGAS/STING in Indian TB patients and healthy cohorts from India and Germany by Lightcycler®480 genotyping technique. The cGAS/STING pathway is an essential defense pathway within the cytosol after M.tb is internalized and mycobacterial DNA is released inducing the production of type I IFNs. We found that the rs311686 SNP upstream of cGAS provides protection from getting TB overall and is differently distributed in pulmonary TB patients compared with extra-pulmonary and particularly relapse cases. This SNP furthermore differs in distribution when comparing individuals with respect to BCG vaccination status. Taken together, our results show that the presence of the rs311686 SNP influences the course of TB significantly. However, structural conformation changes were found only for the cGAS rs610913 SNP. These findings underscore the importance of M.tb DNA recognition for TB pathogenesis and may eventually help in risk stratification of individuals. This may ultimately help in prevention of disease and aid in developing new vaccination and treatment strategies.

Variation analysis of theTMEM150B gene in Chinese women with premature ovarian insufficiency

RESEARCH QUESTION

The TMEM150B gene, which promotes cell survival under stress conditions by modulating autophagy, is closely associated with age at natural menopause, early menopause and premature ovarian insufficiency (POI) in European women. However, whether gene variants of TMEM150B contribute to the pathogenesis of POI needs to be determined.

DESIGN

A case-control genetic study in 408 Han Chinese women with non-syndromic POI, in which all exons and exon-intron boundaries of the TMEM150B gene were screened by Sanger sequencing; the results were analysed by statistics and bioinformatics.

RESULTS

Two novel variants located in the 3' untranslated region of the TMEM150B gene were identified, but bioinformation analyses showed that neither was potentially disease-causing. Six known single-nucleotide polymorphisms (SNP) were found, and they were not potentially causative for POI. The intronic SNP rs11668344 was also detected in the POI patients; no significant differences were found in either genotype or allele frequencies compared with the control population.

CONCLUSION

The results suggest that the perturbations in the TMEM150B gene are not a common explanation for POI in Chinese women. The role of autophagy in the pathogenic mechanism of POI needs further exploration.

Molecular Genetics of Premature Ovarian Insufficiency

Premature ovarian insufficiency (POI) is highly heterogeneous in genetic etiology. Yet identifying causative genes has been challenging with candidate gene approaches. Recent approaches using next generation sequencing (NGS), especially whole exome sequencing (WES), in large POI pedigrees have identified new causatives and proposed relevant candidates, mainly enriched in DNA damage repair, homologous recombination, and meiosis. In the near future, NGS or whole genome sequencing will help better define genes involved in intricate regulatory networks. The research into miRNA and age at menopause represents an emerging field that will help unveil the molecular mechanisms underlying pathogenesis of POI. Shedding light on the genetic architecture is important in interpreting pathogenesis of POI, and will facilitate risk prediction for POI.

Minichromosome maintenance complex component 8 and 9 gene expression in the menstrual cycle and unexplained primary ovarian insufficiency

PURPOSE

DNA repair genes Minichromosome maintenance complex component (MCM) 8 and 9 have been linked with gonadal development, primary ovarian insufficiency (POI), and age at menopause. Our objective was to characterize MCM 8 and 9 gene expression in the menstrual cycle, and to compare MCM 8/9 expression in POI vs normo-ovulatory women.

METHODS

Normo-ovulatory controls (n = 11) and unexplained POI subjects (n = 6) were recruited. Controls provided three blood samples within one menstrual cycle: (1) early follicular phase, (2) ovulation, and (3) mid-luteal phase. Six of 11 controls only provided a follicular phase sample. Amenorrheic POI subjects provided a single, random blood sample. MCM8/9 expression in peripheral blood was assessed with qRTPCR. Analyses were performed using delta-Ct measurements; group differences were transformed to a fold change (FC) and confidence interval (CI). Differences across menstrual cycle phases were compared using random effects ANOVA. Two-sample t tests were used to compare two groups.

RESULTS

MCM8 expression was significantly lower at ovulation and during the luteal phase, when compared to the follicular phase [FC = 0.69 in the luteal vs follicular phase (p = 0.012, CI = 0.53, 0.90); and 0.65 in the ovulatory vs follicular phase (p = 0.0057, CI = 0.50, 0.85)]. No change in MCM9 expression was noted throughout the menstrual cycle. No significant difference was seen in MCM8/9 expression when comparing POI to control subjects.

CONCLUSIONS

Our study showed greater MCM8 expression in the follicular phase of the menstrual cycle, compared to the ovulatory and luteal phases. No cyclic changes were seen with MCM9. Significant differences in MCM8/9 expression were not detected between POI and controls; however, we recommend further investigation with a larger sample population.

Kallmann syndrome: phenotype and genotype of hypogonadotropic hypogonadism

Isolated Gonadotropin-Releasing Hormone (GnRH) Deficiency (IGD) IGD is a genetically and clinically heterogeneous disorder. Mutations in many different genes are able to explain ~40% of the causes of IGD, with the rest of cases remaining genetically uncharacterized. While most mutations are inherited in X-linked, autosomal dominant, or autosomal recessive pattern, several IGD genes are shown to interact with each other in an oligogenic manner. In addition, while the genes involved in the pathogenesis of IGD act on either neurodevelopmental or neuroendocrine pathways, a subset of genes are involved in both pathways, acting as "overlap genes". Thus, some IGD genes play the role of the modifier genes or "second hits", providing an explanation for incomplete penetrance and variable expressivity associated with some IGD mutations. The clinical spectrum of IGD includes a variety of disorders including Kallmann Syndrome (KS), i.e. hypogonadotropic hypogonadism with anosmia, and its normosmic variation normosmic idiopathic hypogonadotropic hypogonadism (nIHH), which represent the most severe aspects of the disorder. Apart from these disorders, there are also "milder" and more common reproductive diseases associated with IGD, including hypothalamic amenorrhea (HA), constitutional delay of puberty (CDP) and adult-onset hypogonadotropic hypogonadism (AHH). Interestingly, neurodeveloplmental genes are associated with the KS form of IGD, due to the topographical link between the GnRH neurons and the olfactory placode. On the other hand, neuroendocrine genes are mostly linked to nIHH. However, a great deal of clinical and genetic overlap characterizes the spectrum of the IGD disorders. IGD is also characterized by a wide variety of non-reproductive features, including midline facial defects such as cleft lip and/or palate, renal agenesis, short metacarpals and other bone abnormalities, hearing loss, synkinesia, eye movement abnormalities, poor balance due to cerebellar ataxia, etc. Therefore, genetic screening should be offered in patients with IGD, as it can provide valuable information for genetic counseling and further understanding of IGD.

Study of patterns of inheritance of premature ovarian failure syndrome carrying maternal and paternal premutations

BACKGROUND

Premature ovarian failure / primary ovarian insufficiency (POF/POI) associated with the mutations of the FMR1 (Fragile-X Mental Retardation 1) gene belongs to the group of the so-called trinucleotide expansion diseases. Our aim was to analyse the relationship between the paternally inherited premutation (PIP) and the maternally inherited premutation (MIP) by the examination of the family members of women with POF, carrying the premutation allele confirmed by molecular genetic testing.

METHODS

Molecular genetic testing was performed in the patients of the 1st Department of Obstetrics and Gynecology with suspected premature ovarian failure. First we performed the southern blot analyses and for the certified premutation cases we used the Repeat Primed PCR.

RESULTS

Due to POF/POI, a total of 125 patients underwent genetic testing. The FMR1 gene trinucleotide repeat number was examined in the DNA samples of the patients, and in 15 cases (12%) deviations (CGG repeat number corresponding to premutation or gray zone) were detected. In 6 cases out of the 15 cases the CGG repeat number fell within the range of the so-called gray zone (41-54 CGG repeat) (4.8%, 6/125), and the FMR1 premutation (55-200 CGG repeat) ratio was 7.2% (9/125). In 4 out of the 15 cases we found differences in both alleles, one was a premutation allele, and the other allele showed a repeat number belonging to the gray zone. Out of 15 cases, only maternal inheritance (MIP) was detected in 2 cases, in one case the premutation allele (91 CGG repeat number), while in the other case an allele belonging to the gray zone (41 CGG repeat number) were inherited from their mothers. In 10 out of 15 cases, the patient inherited the premutation allele only from the father (PIP). In 5 out of the 10 cases (50%) the premutation allele was inherited from the father, and the repeat number ranged from 55 to 133. Out of 125 cases, 9 patients had detectable cytogenetic abnormalities (7.2%).

CONCLUSIONS

The RP-PCR method can be used to define the smaller premutations and the exact CGG number. Due to the quantitative nature of the RP-PCR, it is possible to detect the mosaicism as well.

Maternal gene Ooep may participate in homologous recombination-mediated DNA double-strand break repair in mouse oocytes

DNA damage in oocytes can cause infertility and birth defects. DNA double-strand breaks (DSBs) are highly deleterious and can substantially impair genome integrity. Homologous recombination (HR)-mediated DNA DSB repair plays dominant roles in safeguarding oocyte quantity and quality. However, little is known regarding the key players of the HR repair pathway in oocytes. Here, we identified oocyte-specific gene Ooep as a novel key component of the HR repair pathway in mouse oocytes. OOEP was required for efficient ataxia telangiectasia mutated (ATM) kinase activation and Rad51 recombinase (RAD51) focal accumulation at DNA DSBs. Ooep null oocytes were defective in DNA DSB repair and prone to apoptosis upon exogenous DNA damage insults. Moreover, Ooep null oocytes exhibited delayed meiotic maturation. Therefore, OOEP played roles in preserving oocyte quantity and quality by maintaining genome stability. Ooep expression decreased with the advance of maternal age, suggesting its involvement in maternal aging.