Effect of parental origin and predictors for obtaining a euploid embryo in balanced translocation carriers.

RESEARCH QUESTION: What is the effect of parental origin of translocation and predictors for obtaining a euploid embryo in preimplantation genetic testing for chromosomal structural rearrangements (PGT-SR) for balanced translocation carriers? DESIGN: A total of 179 PGT-SR cycles and 614 blastocysts from 123 couples carrying a balanced translocation were retrospectively analysed. Next-generation sequencing (NGS) was performed after trophectoderm biopsy. RESULTS: There were no differences in ovarian stimulation parameters or PGT-SR outcomes regarding the number of oocytes retrieved (11.95 ± 5.71 versus 11.82 ± 6.26), blastulation rate (0.42 ± 0.27 versus 0.45 ± 0.28), biopsy cancellation rate (11.7% versus 12.9%), the number of blastocysts for biopsy (3.70 ± 2.58 versus 4.04 ± 3.51), or the proportion of euploid embryos (23.80% versus 25.42%), aneuploid embryos (58.10% versus 57.52%) and mosaic embryos (18.10% versus 17.06%) between female carriers and male partner carriers. In a multivariate logistic regression model, the number of blastocysts for biopsy (adjusted odds ratio 1.752; 95% confidence interval 1.359-2.259; P < 0.001) was significantly associated with the chance of obtaining at least one euploid embryo. Receiver operating characteristic analysis with a threshold of 3.5 was conducted to calculate the number of blastocysts required for biopsy to obtain at least one euploid embryo. CONCLUSIONS: The parental origin of translocation does not significantly affect the PGT-SR outcomes for young balanced translocation carriers. At least 3.5 blastocysts are required to obtain one euploid embryo. Couples should be informed that the probability of obtaining one euploid embryo is low when fewer than 4 blastocysts are obtained in one PGT cycle.

Comparison of day 5 blastocyst with day 6 blastocyst: Evidence from NGS-based PGT-A results.

PURPOSE: Aneuploidy is one genetic factor leading to the failure of embryo implantation. This study aimed to investigate the relationship between the day of embryo blastulation and the ploidy status of embryo, to aid in selecting embryos with the most likelihood of of being euploid in a noninvasive way. METHODS: This retrospective study recruited women undergoing preimplantation genetic testing (PGT) for aneuploidy (PGT-A) with trophectoderm biopsy from January 2019 to December 2020. The ploidy status of embryos was determined by next-generation sequencing (NGS). RESULTS: Altogether, 2531 blastocysts from 839 PGT-A cycles were evaluated. The euploid rate of day 5 blastocysts was significantly higher than that of day 6 blastocysts, either from the same ovarian stimulation (OS) cycles (49.9% vs 35.7%, P < 0.001) or from different OS cycles (48.2% vs 27.8%, P < 0.001). This effect of increasing time to embryo blastulation significantly reducing the prevalence of euploidy was not seen in women at age 38 or older. However, after single euploid embryo transfer, the clinical outcomes of day 5 blastocysts were comparable to those of day 6 blastocysts. CONCLUSIONS: In non-PGT cycles, our data support the selection of day 5 blastocysts for transfer over day 6 blastocysts. Further, women with poor ovarian reserve incline to obtain only day 6 blastocysts, and PGT-A is valuable for identifying the ploidy status of embryos, especially for those with advanced age. However, the stage of blastocysts will not affect the clinical outcome after transfer when they are identified as euploid.

SLC39A5 mutations interfering with the BMP/TGF-ß pathway in non-syndromic high myopia.

BACKGROUND: High myopia, with the characteristic feature of refractive error, is one of the leading causes of blindness worldwide. It has a high heritability, but only a few causative genes have been identified and the pathogenesis is still unclear. METHODS: We used whole genome linkage and exome sequencing to identify the causative mutation in a non-syndromic high myopia family. Direct Sanger sequencing was used to screen the candidate gene in additional sporadic cases or probands. Immunofluorescence was used to evaluate the expression pattern of the candidate gene in the whole process of eye development. Real-time quantitative PCR and immunoblot was used to investigate the functional consequence of the disease-associated mutations. RESULTS: We identified a nonsense mutation (c.141C>G:p.Y47*) in SLC39A5 co-segregating with the phenotype in a non-syndromic severe high myopia family. The same nonsense mutation (c.141C>G:p.Y47*) was detected in a sporadic case and a missense mutation (c.911T>C:p.M304T) was identified and co-segregated in another family by screening additional cases. Both disease-associated mutations were not found in 1276 control individuals. SLC39A5 was abundantly expressed in the sclera and retina across different stages of eye development. Furthermore, we found that wild-type, but not disease-associated SLC39A5 inhibited the expression of Smadl, a key phosphate protein in the downstream of the BMP/TGF-ß (bone morphogenic protein/transforming growth factor-ß) pathway. CONCLUSIONS: Our study reveals that loss-of-function mutations of SLC39A5 are associated with the autosome dominant non-syndromic high myopia, and interference with the BMP/TGF-ß pathway may be one of the molecular mechanisms for high myopia.

New ZNF644 mutations identified in patients with high myopia.

PURPOSE: Myopia, or near-sightedness, is one of the most common human visual impairments worldwide, and high myopia is one of the leading causes of blindness. In this study, we investigated the mutation spectrum of ZNF644, a causative gene for autosomal dominant high myopia, in a high-myopia cohort from a Chinese population. METHODS: DNA was isolated with the standard proteinase K digestion and phenol-chloroform method from a case cohort of 186 subjects diagnosed with high myopia (spherical refractive error equal or less than -6.00 diopters). Sanger sequencing was performed to find potential mutations in all coding exons, flanking splicing sites, and untranslated regions (UTRs) of ZNF644 (NM_201269). Identified novel variants were further screened in 526 ethnically matched normal controls. Functional prediction and conservation analysis were performed using ANNOVAR. RESULTS: Five novel variants were identified. Three are missense (c.1201A>G:p.T401A, c.2867C>G:p.T956S, c.3833A>G:p.E1278G), one is synonymous (c.2565A>G:p.T855T), and one (c.-219C>A) is located in the 5' UTR. Functional prediction indicates that c.3833A>G:p.E1278G was predicted to be damaging by SIFT and Polyphen2. Conservation analysis using PhyloP and GERP++ indicate all of the missense variants are highly conserved. None of these novel mutations was identified in 526 normal controls. CONCLUSIONS: ZNF644 is associated with high myopia in a cohort from a Chinese population. ZNF644 mutations have a minor contribution to the genetic etiology of high myopia.

Circular RNA as a Novel Regulator and Promising Biomarker in Polycystic Ovary Syndrome.

Polycystic ovary syndrome (PCOS) is a prevalent metabolic and reproductive disorder that causes low fertility in females. Despite its detrimental effects on women's health, care for PCOS has been impeded by its undefined pathogenesis. Thus, there is an urgent need to explore novel biomarkers and therapeutic targets for the diagnosis and treatment of PCOS. Circular RNAs (circRNAs) are a class of noncoding RNAs with covalently closed cyclic structures, present in high abundance, and show development-stage specific expression patterns. Recent studies have demonstrated that circRNAs participate in PCOS progression by modulating various biological functions, including cell proliferation, apoptosis, and steroidogenesis. In addition, circRNAs are widely present in the follicular fluid of women with PCOS, indicating their potential as diagnostic biomarkers and therapeutic targets for PCOS. This review provides the current knowledge of circRNAs in PCOS, including their regulatory functions and molecular mechanisms, and explores their potential as diagnostic biomarkers and therapeutic targets.

Next-Generation Sequencing (NGS)-Based Preimplantation Genetic Testing for Aneuploidy (PGT-A) of Trophectoderm Biopsy for Recurrent Implantation Failure (RIF) Patients: a Retrospective Study.

Recurrent implantation failure (RIF) is an intrigue condition during in vitro fertilization (IVF) cycles or intracytoplasmic sperm injection (ICSI) treatments. The purpose of this retrospective study is to explore the value of next-generation sequencing (NGS)-based preimplantation genetic testing for aneuploidy (PGT-A) of trophectoderm biopsy in the clinical outcomes for RIF patients with advanced age. A total of 265 RIF patients, who underwent 346 oocyte retrieval cycles and 250 PGT-A cycles, were classified as two groups according to the female age, including < 38 and ≥ 38 years old groups. The two groups were statistically comparable in baseline characteristics. The component of aneuploid embryos was significantly higher in advanced age group than in younger age group (68.9 vs 39.9%, P < 0.001). But there were no statistically significant differences in pregnancy rate (43.5 vs 64.7%), clinical pregnancy rate (39.1 vs 48.0%), implantation rate (39.1 vs 51.0%), and miscarriage rate (4.3 vs 7.8%) per embryo transfer (ET) between the two groups. Results suggest that the embryo-related factor plays a crucial role in RIF. Maternal age does not influence the implantation potential of euploid blastocysts. The NGS-based PGT-A involving trophectoderm biopsy is valuable for RIF patients of advanced age by improving their clinical outcomes. In conclusion, the NGS-based PGT-A involving trophectoderm biopsy may represent a valuable supplement to the current RIF management. Nonetheless, these findings should be further validated in a well-designed randomized controlled trial.

PGT or ICSI? The impression of NGS-based PGT outcomes in nonmosaic Klinefelter syndrome.

This retrospective study demonstrates the clinical outcomes of patients with nonmosaic Klinefelter's syndrome (KS) who underwent preimplantation genetic testing (PGT) with frozen-thawed testicular spermatozoa. Microdissection testicular sperm extraction (micro-TESE) was performed for sperm retrieval. Next-generation sequencing (NGS) was conducted for embryo analysis. A total of 18 couples aged ≤35 years were included, and 22 oocyte retrieval cycles were completed. Euploidy was detected in 29 of 45 (64.4%) embryos. Additionally, the numbers of aneuploid and mosaic embryos detected were 8 (17.8%) and 8 (17.8%), respectively, regardless of a lack of sex chromosome abnormalities. Finally, 13 couples with euploid embryos completed 14 frozen embryo transfer (FET) cycles. Ten couples had clinical pregnancies, and 6 of them had already delivered 5 healthy babies and 1 monozygotic twin. There were also 4 ongoing pregnancies and 2 biochemical pregnancies, but no early pregnancy loss was reported. Based on our results, we speculate that for KS patients, when sperm can be obtained by micro-TESE, the cryopreservation strategy makes the ovarian stimulation procedure more favorable for female partners. The paternal genetic risk of sex chromosome abnormalities in their offspring is extremely low in men with KS. In addition to PGT, the intracytoplasmic sperm injection (ICSI) procedure is comparably effective but more economical for young nonmosaic KS couples. ICSI should be offered as an option for such couples, but monitoring by prenatal genetic diagnosis is recommended.