Application of array comparative genomic hybridization (aCGH) for identification of chromosomal aberrations in the recurrent pregnancy loss

Molecular cytogenetic study of the fetal genome in idiopathic recurrent pregnancy loss

OBJECTIVE

Despite numerous studies on the causes of recurrent pregnancy loss (RPL), nearly half of cases remain unidentified, which determines the research relevance. This study aims to investigate microchromosomal variations in the fetal genome associated with the development of idiopathic RPL.

METHODS

The research was supported by the Centre for Molecular Medicine and the Research Institute of Obstetrics, Gynecology and Perinatology and conducted over a period of 2 years. The study employed the Prepito automatic analyzer from PerkinElmer and the ChemagicPrepito nucleic acid extraction system, to isolate 100 DNA samples from conception products of women with idiopathic RPL, and, subsequently, to analyze for the presence of full-genome chromosomal abnormalities by array comparative genomic hybridisation (aCGH) using CGX-HD microarrays (8x60K), Format 1: CGX (80x60K), a ScanRI microarray scanner (PerkinElmer, Finland), and Genoglyphix, Cytogenomix software.

RESULTS

The study determined that 83% of the materials studied had a normal molecular karyotype, while unbalanced chromosomal abnormalities were detected in 17% of cases, of which 35.3% of abortions had aneuploidies and 64.7% had various structural abnormalities. Among the aneuploidies, 66.7% were trisomies and 33.3% were monosomies. In the group of structural disorders, 81.8% were microdeletions, while microduplications accounted for 18.2%. The data obtained on the frequency and structure of chromosomal abnormalities detected in abortions in the sample surveyed showed that idiopathic RPL is not caused by chromosomal abnormalities of embryos and, unlike all other forms of RPL, has a different cause not related to chromosomal abnormalities.

CONCLUSION

This study conducted molecular cytogenetic analysis of the fetal genome related to RPL. Its findings can help optimize the process of counseling patients with idiopathic RPL.

Revolutionized attitude toward recurrent pregnancy loss and recurrent implantation failure based on precision regenerative medicine

Traditional treatment strategies for recurrent pregnancy loss (RPL) and recurrent implantation failure (RIF) often result in limited success, placing significant emotional and financial burdens on couples. However, novel approaches such as diagnostic gene profiling, cell therapy, stem cell-derived exosome therapy, and pharmacogenomics offer promising, personalized treatments. Combining traditional treatments with precision and regenerative medicine may enhance the efficacy of these approaches and improve pregnancy outcomes. This review explores how integrating these strategies can potentially transform the lives of couples experiencing repeated pregnancy loss or implantation failure, providing hope for improved treatment success. Precision and regenerative medicine represent a new frontier for managing RPL and RIF, offering promising solutions.

Comparative Analysis of Fluorescence In Situ Hybridization and Next-Generation Sequencing in Sperm Evaluation: Implications for Preimplantation Genetic Testing and Male Infertility

Pre-implantation genetic testing (PGT) is a crucial process for selecting embryos created through assisted reproductive technology (ART). Couples with chromosomal rearrangements, infertility, recurrent miscarriages, advanced maternal age, known single-gene disorders, a family history of genetic conditions, previously affected pregnancies, poor embryo quality, or congenital anomalies may be candidates for PGT. Preimplantation genetic testing for aneuploidies (PGT-A) enables the selection and transfer of euploid embryos, significantly enhancing implantation rates in assisted reproduction. Fluorescence in situ hybridization (FISH) is the preferred method for analyzing biopsied cells to identify these abnormalities. While FISH is a well-established method for identifying sperm aneuploidy, NGS offers a more comprehensive assessment of genetic material, potentially enhancing our understanding of male infertility. Chromosomal abnormalities, arising during meiosis, can lead to aneuploid sperm, which may hinder embryo implantation and increase miscarriage rates. This review provides a comparative analysis of fluorescence in situ hybridization (FISH) and next-generation sequencing (NGS) in sperm evaluations, focusing on their implications for preimplantation genetic testing. This analysis explores the strengths and limitations of FISH and NGS, aiming to elucidate their roles in improving ART outcomes and reducing the risk of genetic disorders in offspring. Ultimately, the findings will inform best practices in sperm evaluations and preimplantation genetic testing strategies.

Post-implantation analysis of genomic variations in the progeny from developing fetus to birth

The analysis of genomic variations in offspring after implantation has been infrequently studied. In this study, we aim to investigate the extent of de novo mutations in humans from developing fetus to birth. Using high-depth whole-genome sequencing, 443 parent-offspring trios were studied to compare the results of de novo mutations (DNMs) between different groups. The focus was on fetuses and newborns, with DNA samples obtained from the families' blood and the aspirated embryonic tissues subjected to deep sequencing. It was observed that the average number of total DNMs in the newborns group was 56.26 (54.17-58.35), which appeared to be lower than that the multifetal reduction group, which was 76.05 (69.70-82.40) (F = 2.42, P = 0.12). However, after adjusting for parental age and maternal pre-pregnancy body mass index (BMI), significant differences were found between the two groups. The analysis was further divided into single nucleotide variants (SNVs) and insertion/deletion of a small number of bases (indels), and it was discovered that the average number of de novo SNVs associated with the multifetal reduction group and the newborn group was 49.89 (45.59-54.20) and 51.09 (49.22-52.96), respectively. No significant differences were noted between the groups (F = 1.01, P = 0.32). However, a significant difference was observed for de novo indels, with a higher average number found in the multifetal reduction group compared to the newborn group (F = 194.17, P < 0.001). The average number of de novo indels among the multifetal reduction group and the newborn group was 26.26 (23.27-29.05) and 5.17 (4.82-5.52), respectively. To conclude, it has been observed that the quantity of de novo indels in the newborns experiences a significant decrease when compared to that in the aspirated embryonic tissues (7-9 weeks). This phenomenon is evident across all genomic regions, highlighting the adverse effects of de novo indels on the fetus and emphasizing the significance of embryonic implantation and intrauterine growth in human genetic selection mechanisms.

Causes of Chromosome Breakage and Mis-segregation Affecting Pregnancy and Newborn Health: An Insight into Developing Reproductive Health Preventive Strategies

Chromosome abnormalities are a leading cause of pregnancy loss, developmental delays, and birth defects. These abnormalities arise from errors in chromosome structure (breakage) or number (missegregation) during cell division. Understanding the causes of these errors is crucial for developing effective preventive strategies to improve reproductive health. This paper aims to review the known causes of chromosome breakage and mis-segregation, emphasizing their impact on pregnancy and newborn health. It further explores potential preventive strategies for mitigating these risks. A comprehensive literature review was conducted using relevant databases, focusing on studies investigating the causes of chromosome abnormalities, their impact on pregnancy and newborn health, and potential preventive measures. Several factors contribute to chromosome breakage and mis-segregation, including Genetic Predisposition, Environmental Factors (environmental toxins, radiation), Maternal age, Lifestyle Factors (Smoking, alcohol consumption, and obesity), and Cellular Mechanisms. These abnormalities can manifest as various pregnancy complications, including Miscarriage, stillbirth, birth defects, and developmental Delays. The causes of chromosome breakage and mis-segregation are complex and multifactorial. Understanding these factors is crucial for developing effective preventive strategies. These strategies may include genetic counseling, pre-conception health optimization, environmental hazard mitigation, and advancements in assisted reproductive technologies. Further research is needed to identify specific interventions and personalize strategies based on individual risk factors. Addressing these causes and implementing preventive measures can significantly improve reproductive health outcomes and reduce the incidence of chromosome abnormalities affecting pregnancy and newborn health.

Advancements in copy number variation screening in herbivorous livestock genomes and their association with phenotypic traits

Copy number variations (CNVs) have garnered increasing attention within the realm of genetics due to their prevalence in human, animal, and plant genomes. These structural genetic variations have demonstrated associations with a broad spectrum of phenotypic diversity, economic traits, environmental adaptations, epidemics, and other essential aspects of both plants and animals. Furthermore, CNVs exhibit extensive sequence variability and encompass a wide array of genomes. The advancement and maturity of microarray and sequencing technologies have catalyzed a surge in research endeavors pertaining to CNVs. This is particularly prominent in the context of livestock breeding, where molecular markers have gained prominence as a valuable tool in comparison to traditional breeding methods. In light of these developments, a contemporary and comprehensive review of existing studies on CNVs becomes imperative. This review serves the purpose of providing a brief elucidation of the fundamental concepts underlying CNVs, their mutational mechanisms, and the diverse array of detection methods employed to identify these structural variations within genomes. Furthermore, it seeks to systematically analyze the recent advancements and findings within the field of CNV research, specifically within the genomes of herbivorous livestock species, including cattle, sheep, horses, and donkeys. The review also highlighted the role of CNVs in shaping various phenotypic traits including growth traits, reproductive traits, pigmentation and disease resistance etc., in herbivorous livestock. The main goal of this review is to furnish readers with an up-to-date compilation of knowledge regarding CNVs in herbivorous livestock genomes. By integrating the latest research findings and insights, it is anticipated that this review will not only offer pertinent information but also stimulate future investigations into the realm of CNVs in livestock. In doing so, it endeavors to contribute to the enhancement of breeding strategies, genomic selection, and the overall improvement of herbivorous livestock production and resistance to diseases.

Investigating the "Fetal Side" in Recurrent Pregnancy Loss: Reliability of Cell-Free DNA Testing in Detecting Chromosomal Abnormalities of Miscarriage Tissue

(1) Background: The aim of our study is to evaluate whether cell-free DNA testing can overlap the genetic testing of miscarriage tissue in women with early pregnancy loss (EPL) and length of recurrent pregnancy loss (RPL); (2) Methods: We conducted a prospective cohort study at the Pregnancy Loss Unit of the Fondazione Policlinico Universitario A. Gemelli (IRCCS), Rome, Italy between May 2021 and March 2022. We included women with EPL and length of RPL. Gestational age was >9 weeks + 2 days and <12 weeks + 0 days of gestation corresponding to a crown rump length measurement of >25 and <54 mm. Women underwent both dilation and curettage for the collection of miscarriage tissue and for blood sample collection. Chromosomal microarray analysis (CMA) on miscarriage tissues was performed by oligo-nucleotide- and single nucleotide polymorphisms (SNP)-based comparative genomic hybridization (CGH+SNP). Maternal blood samples were analyzed by Illumina VeriSeq non-invasive prenatal testing (NIPT) to evaluate the cell-free fetal DNA (cfDNA) and the corresponding fetal fraction and the presence of genetic abnormalities; (3) Results: CMA on miscarriage tissues revealed chromosome aneuploidies in 6/10 cases (60%), consisting of trisomy 21 (5 cases) and monosomy X (one case). cfDNA analysis was able to identify all cases of trisomy 21. It failed to detect monosomy X. A large 7p14.1p12.2 deletion concomitant to trisomy 21 was, in one case, detected by cfDNA analysis but it was not confirmed by CMA on miscarriage tissue. (4) Conclusions: cfDNA largely reproduces the chromosomal abnormalities underlying spontaneous miscarriages. However, diagnostic sensitivity of cfDNA analysis is lower with respect to the CMA of miscarriage tissues. In considering the limitations when obtaining biological samples from aborted fetuses suitable for CMA or standard chromosome analysis, cfDNA analysis is a useful, although not exhaustive, tool for the chromosome diagnosis of both early and recurrent pregnancy loss.