Genetic determination of the ovarian reserve: a literature review

BCORL1, POF1B, and USP9X copy number variation in women with idiopathic diminished ovarian reserve

PURPOSE

To analyze the copy number variation (CNV) in the X-linked genes BCORL1, POF1B, and USP9X in idiopathic diminished ovarian reserve (DOR).

METHODS

This case-control study included 47 women, 26 with DOR and 21 in the control group. Age, weight, height, BMI, and FSH level were evaluated, as well as antral follicle count (AFC), oocyte retrieval after controlled ovarian stimulation, and metaphase II (MII) oocytes. The CNVs of BCORL1, USP9X, and POF1B genes were measured by quantitative real time PCR (qPCR) using two reference genes, the HPRT1 (X-linked) and MFN2 (autosomal). Protein-protein interaction network and functional enrichment analysis were performed using the STRING database.

RESULTS

The mean age was 36.52 ± 4.75 in DOR women and 35.38 ± 4.14 in control. Anthropometric measures did not differ between the DOR and control groups. DOR women presented higher FSH (p = 0.0025) and lower AFC (p < .0001), oocyte retrieval after COS (p = 0.0004), and MII oocytes (p < .0001) when compared to the control group. BCORL1 and POF1B did not differ in copy number between DOR and control. However, DOR women had more copies of USP9X than the control group (p = 0.028).

CONCLUSION

The increase in the number of copies of the USP9X gene may lead to overexpression in idiopathic DOR and contribute to altered folliculogenesis and oocyte retrieval.

Analysis of the potential regulatory mechanisms of female and latent genital tuberculosis affecting ovarian reserve function using untargeted metabolomics

Female and latent genital tuberculosis (FGTB and LGTB) in young women may lead to infertility by damaging ovarian reserve function, but the regulatory mechanisms remain unclear. In this study, we investigated the effects of FGTB and LGTB on ovarian reserve function and potential regulatory mechanisms by untargeted metabolomics of follicular fluid, aiming to provide insights for the clinical management and treatment approaches for afflicted women. We recruited 19 patients with FGTB, 16 patients with LGTB, and 16 healthy women as a control group. Clinical data analysis revealed that both the FGTB and LGTB groups had significantly lower ovarian reserve marker levels compared to the control group, including lower anti-Müllerian hormone levels (FGTB: 0.82 [0.6, 1.1] μg/L; LGTB: 1.57 [1.3, 1.8] μg/L vs. control: 3.29 [2.9, 3.5] μg/L), reduced antral follicular counts (FGTB: 6 [5.5, 9.5]; LGTB: 10.5 [7, 12.3] vs. control: 17 [14.5, 18]), and fewer retrieved oocytes (FGTB: 3 [2, 5]; LGTB: 8 [4, 8.3] vs. control: 14.5 [11.5, 15.3]). Conversely, these groups exhibited higher ovarian response marker levels, such as longer gonadotropin treatment days (FGTB: 12 [10.5, 12.5]; LGTB: 11 [10.8, 11.3] vs. control: 10 [8.8, 10]) and increased gonadotropin dosage requirements (FGTB: 3300 [3075, 3637.5] U; LGTB: 3037.5 [2700, 3225] U vs. control: 2531.25 [2337.5, 2943.8] U). All comparisons were statistically significant at P < 0.05. The results suggested that FGTB and LGTB have adverse effects on ovarian reserve and response. Untargeted metabolomic analysis identified 92 and 80 differential metabolites in the control vs. FGTB and control vs. LGTB groups, respectively. Pathway enrichment analysis revealed significant alterations in metabolic pathways in the FGTB and LGTB groups compared to the control group (P < 0.05), with specific changes noted in galactose metabolism, biotin metabolism, steroid hormone biosynthesis, and nicotinate and nicotinamide metabolism in the FGTB group, and caffeine metabolism, primary bile acid biosynthesis, steroid hormone biosynthesis, and glycerophospholipid metabolism in the LGTB group. The analysis of metabolic levels has revealed the potential mechanisms by which FGTB and LGTB affect ovarian reserve function, namely through alterations in metabolic pathways. The study emphasizes the importance of comprehending the metabolic alterations associated with FGTB and LGTB, which is of considerable relevance for the clinical management and therapeutic approaches in afflicted women.

Identification of compound heterozygous variants in MSH4 as a novel genetic cause of diminished ovarian reserve

BACKGROUND

Diminished ovarian reserve (DOR) is a common cause of female infertility, with genetic factors being a significant contributor. However, due to high genetic heterogeneity, the etiology of DOR in many cases remains unknown. In this study, we analyzed the phenotype of a young woman with primary infertility and performed molecular genetic analysis to identify the genetic cause of her condition, thus providing important insights for genetic counseling and reproductive guidance.

METHODS

We collected the patient's basic information, clinical data, as well as diagnostic and therapeutic history and performed whole-exome sequencing on her peripheral blood. Candidate pathogenic variants were validated by Sanger sequencing in family members, and the pathogenicity of variants was analyzed using ACMG guidelines. We used bioinformatics tools to predict variant effects on splicing and protein function, and performed in vitro experiments including minigene assay and expression analysis to evaluate their functional effects on HEK293T.

RESULTS

We identified biallelic MSH4 variants, c.2374 A > G (p.Thr792Ala) and c.2222_2225delAAGA (p.Lys741Argfs*2) in the DOR patient. According to ACMG guidelines, the former was classified as likely pathogenic, while the latter was classified as pathogenic. The patient presented with poor oocyte quantity and quality, resulting in unsuccessful in vitro fertilization cycles. Bioinformatics and in vitro functional analysis showed that the c.2374 A > G variant altered the local conformation of the MutS_V domain without decreasing MSH4 protein expression, while the c.2222_2225delAAGA variant led to a reduction in MSH4 protein expression without impacting splicing.

CONCLUSIONS

In this study, we present evidence of biallelic variants in MSH4 as a potential cause of DOR. Our findings indicate a correlation between MSH4 variants and reduced oocyte quality, as well as abnormal morphology of the first polar body, thereby expanding the phenotypic spectrum associated with MSH4 variants. Furthermore, Our study emphasizes the importance of utilizing whole-exome sequencing and functional analysis in diagnosing genetic causes, as well as providing effective genetic counseling and reproductive guidance for DOR patients.

Single-Cell Transcriptomics Analysis Reveals a Cell Atlas and Cell Communication in Yak Ovary

Yaks (Bos grunniens) are the only bovine species that adapt well to the harsh high-altitude environment in the Qinghai-Tibetan plateau. However, the reproductive adaptation to the climate of the high elevation remains to be elucidated. Cell composition and molecular characteristics are the foundation of normal ovary function which determines reproductive performance. So, delineating ovarian characteristics at a cellular molecular level is conducive to elucidating the mechanism underlying the reproductive adaption of yaks. Here, the single-cell RNA-sequencing (scRNA-seq) was employed to depict an atlas containing different cell types with specific molecular signatures in the yak ovary. The cell types were identified on the basis of their specifically expressed genes and biological functions. As a result, a cellular atlas of yak ovary was established successfully containing theca cells, stromal cells, endothelial cells, smooth muscle cells, natural killer cells, macrophages, and proliferating cells. A cell-to-cell communication network between the distinct cell types was constructed. The theca cells were clustered into five subtypes based on their biological functions. Further, CYP11A1 was confirmed as a marker gene for the theca cells by immunofluorescence staining. Our work reveals an ovarian atlas at the cellular molecular level and contributes to providing insights into reproductive adaption in yaks.

WT1, NR0B1, NR5A1, LHX9, ZFP92, ZNF275, INSL3, and NRIP1 Genetic Variants in Patients with Premature Ovarian Insufficiency in a Mexican Cohort

Premature ovarian insufficiency (POI) is one of the main causes of female premature infertility. POI is a genetically heterogeneous disorder with a complex molecular etiology; as such, the genetic causes remain unknown in the majority of patients. Therefore, this study aimed to identify mutations and characterize the associated molecular contribution of gonadogenesis-determinant genes to POI. Genomic assays, including PCR-SSCP and Sanger sequencing, followed by in silico analyses were used to investigate the underpinnings of ovarian deficiency in 11 women affected by POI. Large deletions and nucleotide insertions and duplications were excluded by PCR. Thirteen genetic variants were identified in the WT1 (c.213G>T, c.609T>C, c.873A>G, c.1122G>A), NR0B1 (c.353C>T, c.425G>A), NR5A1 (c.437G>C, IVS4-20C>T), LHX9 (IVS2-12G>C, IVS3+13C>T, c.741T>C), ZNF275 (c.969C>T), and NRIP1 (c.3403C>T) genes. Seven novel genetic variants and five unpublished substitutions were identified. No genetic aberrations were detected in the ZFP92 and INSL3 genes. Each variant was genotyped using PCR-SSCP in 100 POI-free subjects, and their allelic frequencies were similar to the patients. These analyses indicated that allelic variation in the WT1, NR0B1, NR5A1, LHX9, ZFP92, ZNF275, INSL3, and NRIP1 genes may be a non-disease-causing change or may not contribute significantly to the genetics underlying POI disorders. Findings support the polygenic nature of this clinical disorder, with the SNVs identified representing only a probable contribution to the variability of the human genome.