MCM8 interacts with DDX5 to promote R-loop resolution.

MCM8 has emerged as a core gene in reproductive aging and is crucial for meiotic homologous recombination repair. It also safeguards genome stability by coordinating the replication stress response during mitosis, but its function in mitotic germ cells remains elusive. Here we found that disabling MCM8 in mice resulted in proliferation defects of primordial germ cells (PGCs) and ultimately impaired fertility. We further demonstrated that MCM8 interacted with two known helicases DDX5 and DHX9, and loss of MCM8 led to R-loop accumulation by reducing the retention of these helicases at R-loops, thus inducing genome instability. Cells expressing premature ovarian insufficiency-causative mutants of MCM8 with decreased interaction with DDX5 displayed increased R-loop levels. These results show MCM8 interacts with R-loop-resolving factors to prevent R-loop-induced DNA damage, which may contribute to the maintenance of genome integrity of PGCs and reproductive reserve establishment. Our findings thus reveal an essential role for MCM8 in PGC development and improve our understanding of reproductive aging caused by genome instability in mitotic germ cells.

Transcription-replication conflicts in primordial germ cells necessitate the Fanconi anemia pathway to safeguard genome stability.

Preserving a high degree of genome integrity and stability in germ cells is of utmost importance for reproduction and species propagation. However, the regulatory mechanisms of maintaining genome stability in the developing primordial germ cells (PGCs), in which rapid proliferation is coupled with global hypertranscription, remain largely unknown. Here, we find that mouse PGCs encounter a constitutively high frequency of transcription-replication conflicts (TRCs), which lead to R-loop accumulation and impose endogenous replication stress on PGCs. We further demonstrate that the Fanconi anemia (FA) pathway is activated by TRCs and has a central role in the coordination between replication and transcription in the rapidly proliferating PGCs, as disabling the FA pathway leads to TRC and R-loop accumulation, replication fork destabilization, increased DNA damage, dramatic loss of mitotically dividing mouse PGCs, and consequent sterility of both sexes. Overall, our findings uncover the unique source and resolving mechanism of endogenous replication stress during PGC proliferation, provide a biological explanation for reproductive defects in individuals with FA, and improve our understanding of the monitoring strategies for genome stability during germ cell development.

DNA repair protein FANCD2 has both ubiquitination-dependent and ubiquitination-independent functions during germ cell development.

When DNA interstrand crosslink lesions occur, a core complex of Fanconi anemia proteins promotes the ubiquitination of FANCD2 and FANCI, which recruit downstream factors to repair the lesion. However, FANCD2 maintains genome stability not only through its ubiquitination-dependent but also its ubiquitination-independent functions in various DNA damage response pathways. Increasing evidence suggests that FANCD2 is essential for fertility, but its ubiquitination-dependent and ubiquitination-independent roles during germ cell development are not well characterized. In this study, we analyzed germ cell development in Fancd2 KO and ubiquitination-deficient mutant (Fancd2K559R/K559R) mice. We showed that in the embryonic stage, both the ubiquitination-dependent and ubiquitination-independent functions of FANCD2 were required for the expansion of primordial germ cells and establishment of the reproductive reserve by reducing transcription-replication conflicts and thus maintaining genome stability in primordial germ cells. Furthermore, we found that during meiosis in spermatogenesis, FANCD2 promoted chromosome synapsis and regulated crossover formation independently of its ubiquitination, but that both ubiquitinated and nonubiquitinated FANCD2 functioned in programmed double strand break repair. Finally, we revealed that on meiotic XY chromosomes, H3K4me2 accumulation required ubiquitination-independent functionality of FANCD2, while the regulation of H3K9me2 and H3K9me3 depended on FANCD2 ubiquitination. Taken together, our findings suggest that FANCD2 has distinct functions that are both dependent on and independent of its ubiquitination during germ cell development.

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.

Live Birth with or without Preimplantation Genetic Testing for Aneuploidy.

BACKGROUND: Embryo selection with preimplantation genetic testing for aneuploidy (PGT-A) may improve pregnancy outcomes after initial embryo transfer. However, it remains uncertain whether PGT-A improves the cumulative live-birth rate as compared with conventional in vitro fertilization (IVF). METHODS: In this multicenter, randomized, controlled trial, we randomly assigned subfertile women with three or more good-quality blastocysts to undergo either PGT-A or conventional IVF; all the women were between 20 and 37 years of age. Three blastocysts were screened by next-generation sequencing in the PGT-A group or were chosen by morphologic criteria in the conventional-IVF group and then were successively transferred one by one. The primary outcome was the cumulative live-birth rate after up to three embryo-transfer procedures within 1 year after randomization. We hypothesized that the use of PGT-A would result in a cumulative live-birth rate that was no more than 7 percentage points higher than the rate after conventional IVF, which would constitute the noninferiority margin for conventional IVF as compared with PGT-A. RESULTS: A total of 1212 patients underwent randomization, and 606 were assigned to each trial group. Live births occurred in 468 women (77.2%) in the PGT-A group and in 496 (81.8%) in the conventional-IVF group (absolute difference, -4.6 percentage points; 95% confidence interval [CI], -9.2 to -0.0; P<0.001). The cumulative frequency of clinical pregnancy loss was 8.7% and 12.6%, respectively (absolute difference, -3.9 percentage points; 95% CI, -7.5 to -0.2). The incidences of obstetrical or neonatal complications and other adverse events were similar in the two groups. CONCLUSIONS: Among women with three or more good-quality blastocysts, conventional IVF resulted in a cumulative live-birth rate that was noninferior to the rate with PGT-A. (Funded by the National Natural Science Foundation of China and others; ClinicalTrials.gov number, NCT03118141.).

PDCD4 deficiency improved 4-vinylcyclohexene dioxide-induced mouse premature ovarian insufficiency.

RESEARCH QUESTION: What role does programmed cell death 4 (PDCD4) play in premature ovarian insufficiency (POI)? DESIGN: A PDCD4 gene knockout (PDCD4-/-) mouse model was constructed, a POI mouse model was established similar to human POI with 4-vinylcyclohexene dioxide (VCD), a PDCD4-overexpressed adenovirus was designed and the regulatory role in POI in vitro and in vivo was investigated. RESULTS: PDCD4 expression was significantly increased in the ovarian granulosa cells of patients with POI (P ≤ 0.002 protein and mRNA) and mice with VCD-induced POI (P < 0.001 protein expression in both mouse ovaries and granulosa cells). In POI-induced mice model, PDCD4 knockouts significantly increased anti-Müllerian hormone, oestrodiol and numbers of developing follicles, and the PI3K-AKT-Bcl2/Bax signalling pathway is involved in it. CONCLUSION: The expression and regulation of PDCD4 significantly affects the POI pathology in a mouse model. This effect is closely related to the regulation of Bcl2/Bax and the activation of the PI3K-AKT signalling pathway.

UBE2T resolves transcription-replication conflicts and protects common fragile sites in primordial germ cells.

The proper development of primordial germ cells (PGCs) is an essential prerequisite for gametogenesis and mammalian fertility. The Fanconi anemia (FA) pathway functions in maintaining the development of PGCs. FANCT/UBE2T serves as an E2 ubiquitin-conjugating enzyme that ubiquitylates the FANCD2-FANCI complex to activate the FA pathway, but its role in the development of PGCs is not clear. In this study, we found that Ube2t knockout mice showed defects in PGC proliferation, leading to severe loss of germ cells after birth. Deletion of UBE2T exacerbated DNA damage and triggered the activation of the p53 pathway. We further demonstrated that UBE2T counteracted transcription-replication conflicts by resolving R-loops and stabilizing replication forks, and also protected common fragile sites by resolving R-loops in large genes and promoting mitotic DNA synthesis to maintain the genome stability of PGCs. Overall, these results provide new insights into the function and regulatory mechanisms of the FA pathway ensuring normal development of PGCs.

FAAP100 is required for the resolution of transcription-replication conflicts in primordial germ cells.

BACKGROUND: The maintenance of genome stability in primordial germ cells (PGCs) is crucial for the faithful transmission of genetic information and the establishment of reproductive reserve. Numerous studies in recent decades have linked the Fanconi anemia (FA) pathway with fertility, particularly PGC development. However, the role of FAAP100, an essential component of the FA core complex, in germ cell development is unexplored. RESULTS: We find that FAAP100 plays an essential role in R-loop resolution and replication fork protection to counteract transcription-replication conflicts (TRCs) during mouse PGC proliferation. FAAP100 deletion leads to FA pathway inactivation, increases TRCs as well as cotranscriptional R-loops, and contributes to the collapse of replication forks and the generation of DNA damage. Then, the activated p53 signaling pathway triggers PGC proliferation defects, ultimately resulting in insufficient establishment of reproductive reserve in both sexes of mice. CONCLUSIONS: Our findings suggest that FAAP100 is required for the resolution of TRCs in PGCs to safeguard their genome stability.

Mapping and Screening of Candidate Gene Regulating the Biomass Yield of Sorghum (Sorghum bicolor L.).

Biomass yield is one of the important traits of sorghum, which is greatly affected by leaf morphology. In this study, a lobed-leaf mutant (sblob) was screened and identified, and its F2 inbred segregating line was constructed. Subsequently, MutMap and whole-genome sequencing were employed to identify the candidate gene (sblob1), the locus of which is Sobic.003G010300. Pfam and homologous analysis indicated that sblob1 encodes a Cytochrome P450 protein and plays a crucial role in the plant serotonin/melatonin biosynthesis pathway. Structural and functional changes in the sblob1 protein were elucidated. Hormone measurements revealed that sblob1 regulates both leaf morphology and sorghum biomass through regulation of the melatonin metabolic pathway. These findings provide valuable insights for further research and the enhancement of breeding programs, emphasizing the potential to optimize biomass yield in sorghum cultivation.

Pathogenic bi-allelic variants of meiotic ZMM complex gene SPO16 in premature ovarian insufficiency.

Premature ovarian insufficiency (POI) is a heterogeneous disease affecting the physical and mental health of millions of women worldwide. The contribution of genetic factors in the pathogenesis of POI has increased, with quite a few of causative genes involved in meiosis. ZMM proteins are a group of conserved proteins participating in meiotic synapsis and crossover maturation. Here, by screening the variations of ZMM genes in our in-house WES database of 1030 idiopathic POI patients, one novel homozygous variation in SPO16 (c.160 + 8A > G) was firstly identified in one patient. The variation was verified to disturb mRNA splicing by minigene assay, produced a non-functional SPO16 protein, and was classified as pathogenetic according to American College of Medical Genetics guideline. During meiotic prophase I, SHOC1 binds to branched DNA and recruits SPO16 and other ZMM proteins to facilitate crossover formation. Together with our recent identified bi-allelic variations of SHOC1 in a published work, this study highlighted the essential roles of ZMM genes in the maintenance of ovarian function and expanded the POI gene spectrum.

3D full-wave multi-scattering forward solver for coherent microscopes.

A rigorous forward model solver for conventional coherent microscope is presented. The forward model is derived from Maxwell's equations and models the wave behaviour of light matter interaction. Vectorial waves and multiple-scattering effect are considered in this model. Scattered field can be calculated with given distribution of the refractive index of the biological sample. Bright field images can be obtained by combining the scattered field and reflected illumination, and experimental validation is included. Insights into the utility of the full-wave multi-scattering (FWMS) solver and comparison with the conventional Born approximation based solver are presented. The model is also generalizable to the other forms of label-free coherent microscopes, such as quantitative phase microscope and dark-field microscope.

The impact of previous conservative treatment of atypical hyperplasia on pregnancy outcomes after IVF/ICSI-embryo transfer: a propensity score-matched retrospective cohort study.

STUDY QUESTION: Do women have worse pregnancy and neonatal outcomes of IVF/ICSI-fresh embryo transfer (ET) after conservative treatment of atypical hyperplasia (AH)? SUMMARY ANSWER: AH has no impact on live birth but is associated with increased risks of pregnancy loss and preterm delivery (PTD). WHAT IS KNOWN ALREADY: AH is a precancerous lesion of endometrial cancer. Several recognized AH risk factors include nulliparity, increased body mass index, ovulation disorders, diabetes mellitus, and others. As such, patients are suggested to attempt conception upon achieving AH regression. Recently, successful pregnancies with IVF/ICSI have been increasingly reported. STUDY DESIGN, SIZE, DURATION: Forty-two patients with AH regression and 18 700 women with no evidence of endometrial abnormality, who underwent their first autologous oocytes' retrieval and fresh ET cycles of IVF/ICSI in the Center for Reproductive Medicine, Shandong University, from May 2008 to July 2021, were retrospectively enrolled. PARTICIPANTS/MATERIALS, SETTING, METHODS: First, 42 AH patients were propensity score matched with control women (n = 168) at a 1:4 ratio. Reproductive outcomes and maternal/neonatal complications were compared between the matched pairs. Binary logistic regression analyses were conducted to assess odds ratios (ORs) of AH for live birth, pregnancy loss, and PTD from AH women and all 18 700 eligible controls. MAIN RESULT AND THE ROLE OF CHANCE: Patients with AH achieved a numerically lower live birth rate (LBR) as compared to the matched controls, but without significant difference (26% versus 37%, P = 0.192). However, compared with the matched controls, AH patients showed significantly higher rates of pregnancy loss (52% versus 21%, P = 0.003) and PTD (45% versus 16%, P = 0.041). Further analyses revealed a statistically significantly increased rate of late pregnancy loss (17% versus 3%, P = 0.023), but not early miscarriage (35% versus 18%, P = 0.086), in the AH group. Furthermore, after correcting for potential confounders, the likelihood of a live birth in AH patients narrowly failed to be statistically significantly different from controls (adjusted OR [aOR]: 0.51, 95% CI: 0.25-1.04, P = 0.064). Nonetheless, the logistic regression reconfirmed that AH was an independent risk factor for pregnancy loss (aOR: 3.62, 95% CI: 1.55-8.46, P = 0.003), late pregnancy loss (aOR: 9.33, 95% CI: 3.00-29.02, P < 0.001), and PTD (aOR: 5.70, 95% CI: 1.45-22.38, P = 0.013). LIMITATIONS, REASONS FOR CAUTION: Selection bias was an inherent drawback of this study. First, because of the low AH prevalence among women receiving IVF/ICSI treatment, and consequently, limited sample size, the relationship between AH with LBR and adverse complications might be concealed and underestimated. Hence, the results should be interpreted cautiously. Similarly, the impacts of diverse clinical features of AH patients on the pregnancy outcomes need further studies in a larger population. Second, although most data used in this study were obtained by reviewing the medical records, missing data did exist and so did the recall bias. Third, although the propensity score matching and multivariable logistic models were performed collectively in order to minimize potential confounders between AH and controls, the intrinsic disadvantages of the retrospective nature of this study could not be avoided completely, and additional confirmation bias might be induced with reduplication of statistical analyses. WIDER IMPLICATION OF THE FINDINGS: Our results highlight the necessity of adequate counseling and intensive pregnancy monitoring for AH individuals and their families. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by grants from the National Key Research & Developmental Program of China (2022YFC2703800), the Natural Science Foundation of Shandong Province (ZR2022MH009), and Projects of Medical and Health Technology Development Program in Shandong Province (202005010520, 202005010523). There are no conflicts of interest to declare. TRIAL REGISTRATION NUMBER: N/A.

Homozygous missense variant in MEIOSIN causes premature ovarian insufficiency.

STUDY QUESTION: Are variants of genes involved in meiosis initiation responsible for premature ovarian insufficiency (POI)? SUMMARY ANSWER: A MEIOSIN variant participates in the pathogenesis of human POI by impairing meiosis due to insufficient transcriptional activation of essential meiotic genes. WHAT IS KNOWN ALREADY: Meiosis is the key event for the establishment of the ovarian reserve, and several gene defects impairing meiotic homologous recombination have been found to contribute to the pathogenesis of POI. Although STRA8 and MEIOISN variants have been found to associate with POI in a recent study, the condition of other meiosis initiation genes is unknown and direct evidence of variants participating in the pathogenesis of POI is still lacking. STUDY DESIGN, SIZE, DURATION: This was a retrospective genetic study. An in-house whole exome sequencing (WES) database of 1030 idiopathic POI patients was screened for variations of meiosis initiation genes. PARTICIPANTS/MATERIALS, SETTING, METHODS: Homozygous or compound heterozygous variations of genes involved in meiosis initiation were screened in the in-house WES database. The pathogenicity of the variation was verified by in vitro experiments, including protein structure prediction and dual-luciferase reporter assay. The effect of the variant on ovarian function and meiosis was demonstrated through histological analyses in a point mutation mouse model. MAIN RESULTS AND THE ROLE OF CHANCE: One homozygous variant in MEIOSIN (c.1735C>T, p.R579W) and one in STRA8 (c.258 + 1G>A), which initiates meiosis via the retinoic acid-dependent pathway, were identified in a patient with idiopathic POI respectively. The STRA8 variation has been reported in the recently published work. For the MEIOSIN variation, the dual-luciferase reporter assay revealed that the variant adversely affected the transcriptional function of MEIOSIN in upregulating meiotic genes. Furthermore, knock-in mice with the homologous mutation confirmed that the variation impacted the meiotic prophase I program and accelerated oocyte depletion. Moreover, the variant p.R579W localizing in the high-mobility group (HMG) box domain disrupted the nuclear localization of the MEIOSIN protein but was dispensable for the cell-cycle switch of oocytes, suggesting a unique role of the MEIOSIN HMG box domain in meiosis initiation. LIMITATIONS, REASONS FOR CAUTION: Further studies are needed to explore the role of other meiosis initiation genes in the pathogenesis of POI. WIDER IMPLICATIONS OF THE FINDINGS: The MEIOSIN variant was verified to cause POI by impaired transcriptional regulation of meiotic genes and was inherited by a recessive mode. The function of HMG box domain in MEIOSIN protein was also expanded by this study. Although causative variations in meiotic initiation genes are rare in POI, our study confirmed the pathogenicity of a MEIOSIN variant and elucidated another mechanism of human infertility. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by the National Key Research & Developmental Program of China (2022YFC2703800, 2022YFC2703000), National Natural Science Foundation for Distinguished Young Scholars (82125014), National Natural Science Foundation of China (32070847, 32170867, 82071609), Basic Science Center Program of NSFC (31988101), Natural Science Foundation of Shandong Province for Grand Basic Projects (ZR2021ZD33), Natural Science Foundation of Shandong Province for Excellent Young Scholars (ZR2022YQ69), Taishan Scholars Program for Young Experts of Shandong Province (tsqn202211371), and Qilu Young Scholars Program of Shandong University. The authors declare no conflict of interest. TRIAL REGISTRATION NUMBER: N/A.

Maternal and neonatal complications after IVF/ICSI-fresh embryo transfer in low-prognosis women under the POSEIDON criteria: a retrospective cohort study.

BACKGROUND: Several studies on pregnancy complications of poor ovarian response (POR) patients did not draw a consistent conclusion. The POSEIDON criteria introduces the concept of "low prognosis" and divides POR patients into four groups based on age, AFC and AMH for individualized management. We analyzed low-prognosis population and patients with regular ovarian response, compared maternal and neonatal complications and discussed the relevant risk factors. METHODS: A retrospective cohort study was conducted of females who achieved a singleton clinical pregnancy after IVF / ICSI-fresh embryo transfer in a single center from January 2014 to March 2019. Participants with low prognosis, as defined by the POSEIDON criteria, were enrolled in the study groups. The controls were defined as AFC ≥ five and number of retrieved oocytes > nine. Maternal and neonatal complications were compared among those groups. RESULTS: There were 2554 cycles in POSEIDON group 1, 971 in POSEIDON group 2, 141 in POSEIDON group 3, 142 in POSEIDON group 4, and 3820 in Control. Univariate analysis roughly showed that Groups 2 and 4 had an increased tendency of pregnancy complications. Multi-variable generalized estimating equations (GEE) analysis showed that the risks of GDM, total pregnancy loss, and first-trimester pregnancy loss in Groups 2 and 4 were significantly higher than in Control. The risk of hypertensive disorders of pregnancy (HDP) in Groups 2 and 3 increased, and Group 4 had an increased tendency without statistical significance. After classification by age, GEE analysis showed no significant difference in risks of all complications among groups ≥ 35 years. In patients < 35 years, the risk of HDP in POSEIDON group 3 was significantly higher than in controls (< 35 years), and there was no significant increase in the risk of other complications. CONCLUSION: Compared to patients with regular ovarian response, low-prognosis population have increased tendency of maternal and neonatal complications. In low-prognosis patients, advanced age (≥ 35 years) might be the predominant risk factor for pregnancy complications. In those < 35 years, poor ovarian reserve could contribute to HDP.

Rare deleterious BUB1B variants induce premature ovarian insufficiency and early menopause.

Losing of ovarian functions prior to natural menopause age causes female infertility and early menopause. Premature ovarian insufficiency (POI) is defined as the loss of ovarian activity before 40 years of age. Known genetic causes account for 25-30% of POI cases, demonstrating the high genetic heterogeneity of POI and the necessity for further genetic explorations. Here we conducted genetic analyses using whole-exome sequencing in a Chinese non-syndromic POI family with the affected mother and at least four affected daughters. Intriguingly, a rare missense variant of BUB1B c.273A>T (p.Gln91His) was shared by all the cases in this family. Furthermore, our replication study using targeted sequencing revealed a novel stop-gain variant of BUB1B c.1509T>A (p.Cys503*) in one of 200 sporadic POI cases. Both heterozygous BUB1B variants were evaluated to be deleterious by multiple in silico tools. BUB1B encodes BUBR1, a crucial spindle assembly checkpoint component involved in cell division. BUBR1 insufficiency may induce vulnerability to oxidative stress. Therefore, we generated a mouse model with a loss-of-function mutant of Bub1b, and also employed D-galactose-induced aging assays for functional investigations. Notably, Bub1b+/- female mice presented late-onset subfertility, and they were more sensitive to oxidative stress than wild-type female controls, mimicking the clinical phenotypes of POI cases affected by deleterious BUB1B variants. Our findings in human cases and mouse models consistently suggest, for the first time, that heterozygous deleterious variants of BUB1B are involved in late-onset POI and related disorders.

Genome Sequencing Explores Complexity of Chromosomal Abnormalities in Recurrent Miscarriage.

Recurrent miscarriage (RM) affects millions of couples globally, and half of them have no demonstrated etiology. Genome sequencing (GS) is an enhanced and novel cytogenetic tool to define the contribution of chromosomal abnormalities in human diseases. In this study we evaluated its utility in RM-affected couples. We performed low-pass GS retrospectively for 1,090 RM-affected couples, all of whom had routine chromosome analysis. A customized sequencing and interpretation pipeline was developed to identify chromosomal rearrangements and deletions/duplications with confirmation by fluorescence in situ hybridization, chromosomal microarray analysis, and PCR studies. Low-pass GS yielded results in 1,077 of 1,090 couples (98.8%) and detected 127 chromosomal abnormalities in 11.7% (126/1,077) of couples; both members of one couple were identified with inversions. Of the 126 couples, 39.7% (50/126) had received former diagnostic results by karyotyping characteristic of normal human male or female karyotypes. Low-pass GS revealed additional chromosomal abnormalities in 50 (4.0%) couples, including eight with balanced translocations and 42 inversions. Follow-up studies of these couples showed a higher miscarriage/fetal-anomaly rate of 5/10 (50%) compared to 21/93 (22.6%) in couples with normal GS, resulting in a relative risk of 2.2 (95% confidence interval, 1.1 to 4.6). In these couples, this protocol significantly increased the diagnostic yield of chromosomal abnormalities per couple (11.7%) in comparison to chromosome analysis (8.0%, chi-square test p = 0.000751). In summary, low-pass GS identified underlying chromosomal aberrations in 1 in 9 RM-affected couples, enabling identification of a subgroup of couples with increased risk of subsequent miscarriage who would benefit from a personalized intervention.

Bi-allelic SPATA22 variants cause premature ovarian insufficiency and nonobstructive azoospermia due to meiotic arrest.

The genetic causes of idiopathic premature ovarian insufficiency (POI) and nonobstructive azoospermia (NOA) remain unclear. We performed whole-exome sequencing (WES) in members of a consanguineous family with two POI and two NOA patients to screen for potential pathogenic variants for familial POI and NOA. And a homozygous variant in SPATA22 (c.400C>T:p.R134X) was identified. Histological analysis and spermatocyte spreading assay demonstrated that the spermatogenesis was arrested at a zygotene-like stage in the proband with NOA. The candidate gene was further screened in the in-house WES database of idiopathic POI-affected patients. One additional compound heterozygous variant in SPATA22 (c.900+1G>A and c.31C>T:p.R11X) was found in one patient with sporadic POI and validated by minigene assay. Thus, this is the first report identifying SPATA22 as the causative gene for human POI. Combined with the observations in the familial patient with NOA, our findings highlighted the essential role of meiotic HR genes in gametogenesis and gonadal function maintenance.

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.

Blastocyst euploidy rates in low-prognosis patients according to the POSEIDON criteria: a retrospective analysis of 3016 embryos.

RESEARCH QUESTION: Do embryo euploidy rates differ in the four groups of women with low prognosis as stratified by the POSEIDON criteria? DESIGN: This was a retrospective cohort study of low-prognosis patients who met the POSEIDON criteria and underwent preimplantation genetic testing for aneuploidies (PGT-A) from January 2013 to June 2020 at the Center for Reproductive Medicine, Shandong University, China. A total of 3016 blastocysts from 1269 PGT-A cycles were included in the study. The primary outcome was the euploidy rate of the blastocysts. For each group, regression analyses were performed to quantitatively describe the relationship between maternal age and embryo euploidy rate. RESULTS: The euploidy rate of embryos in women with poor ovarian response (POR) was 39.1% in total. There were 727, 1052, 275 and 962 blastocysts in groups 1, 2, 3 and 4, respectively, with corresponding embryo euploidy rates of 57.2%, 34.9%, 52.4% and 26.2% (P < 0.001). Within each group, the euploidy rate decreased with age, especially in women aged 35 years or older (i.e. groups 2 and 4). CONCLUSIONS: Euploidy rates were more favourable in groups 1 and 3, of a young age, re-emphasizing that oocyte quality is the primary factor determining embryo euploidy rate. The study's findings demonstrated the reasonability of categorizing women with POR by the POSEIDON criteria depending on female age and ovarian reserve biomarkers. These results also provide information for women with POR in different subgroups so they can receive proper counselling on the possible prognosis.

Association between thyroid autoimmunity and the decline of ovarian reserve in euthyroid women.

RESEARCH QUESTION: Is thyroid autoimmunity (TAI) associated with the decline of ovarian reserve in euthyroid women? DESIGN: Case-control study. Data from 4302 euthyroid women with normal ovarian reserve (NOR) and low ovarian reserve (LOR), including biochemical premature ovarian insufficiency (POI) and overt POI, were retrospectively analysed. The prevalence and effect of TAI on ovarian reserve was evaluated between women with NOR and LOR. Status of ovarian insufficiency and TSH levels was further stratified for analysis. The correlation between anti-thyroid peroxidase antibody (TPOAb), anti-thyroglobulin antibody (TgAb) titres and ovarian reserve markers was also determined. RESULTS: The prevalence of positive TAI and TgAb was equally distributed between women with NOR and LOR (P = 0.080, P = 0.172); the prevalence of TPOAb positivity was higher in the LOR group (P = 0.005). After stratifying ovarian reserve and TSH, positive TAI, TPOAb and TGAb were significantly associated with overt POI when TSH was >2.5 µIU/ml (all P < 0.001); no association was observed with biochemical POI or overt POI when TSH was ≤2.5 µIU/ml. No correlation was found between TPOAb, TGAb titres and AMH (P = 0.218, P = 0.368, respectively), and bilateral AFC (P = 0.184, P = 0.315, respectively) in patients with LOR; only TPOAb titre was positively correlated with FSH (P = 0.039). CONCLUSIONS: Among the whole population of euthyroid women, TAI was not associated with low ovarian reserve but was significantly associated with overt POI in women with TSH>2.5 µIU/ml. Further basic studies on underlying mechanisms are needed.