Abnormal Number Of Chromosomes Research Articles

Characterizing the allele-specific gene expression landscape in high hyperdiploid acute lymphoblastic leukemia with BASE.

Somatic copy number variations (CNVs), including abnormal chromosome numbers and structural changes leading to gain or loss of genetic material, play a crucial role in initiation and progression of cancer. CNVs are believed to cause gene dosage imbalances and modify cis-regulatory elements, leading to allelic expression imbalances in genes that influence cell division and thereby contribute to cancer development. However, the impact of CNVs on allelic gene expression in cancer remains unclear. Allele-specific expression (ASE) analysis, a potent method for investigating genome-wide allelic imbalance profiles in tumors, assesses the relative expression of two alleles using high-throughput sequencing data. However, many existing methods for gene-level ASE detection rely on only RNA sequencing data, which present challenges in interpreting the genetic mechanisms underlying ASE in cancer. To address this issue, we developed a robust framework that integrates allele-specific copy number calls into ASE calling algorithms by leveraging paired genome and transcriptome data from the same sample. This integration enhances the interpretability of the genetic mechanisms driving ASE, thereby facilitating the identification of driver events triggered by CNVs in cancer. In this study, we utilized BASE to conduct a comprehensive analysis of ASE in high hyperdiploid acute lymphoblastic leukemia (HeH ALL), a prevalent childhood malignancy characterized by gains of chromosomes X, 4, 6, 10, 14, 17, 18, and 21. Our analysis unveiled the comprehensive ASE landscape in HeH ALL. Through a multi-perspective examination of HeH ASEs, we offer a systematic understanding of how CNVs impact ASE in HeH, providing valuable insights to guide ASE studies in cancer.

Aneuploidy of Specific Chromosomes is Beneficial to Cells Lacking Spindle Checkpoint Protein Bub3.

Accurate chromosome segregation is crucial for the proper development of all living organisms. Errors in chromosome segregation can lead to aneuploidy, characterized by an abnormal number of chromosomes, which generally impairs cell survival and growth. However, under certain stress conditions, such as in various cancers, cells with specific mutations and extra copies of advantageous chromosomes exhibit improved survival and proliferation. In our study, we discovered that cells lacking the spindle checkpoint protein Bub3 became aneuploid, retaining specific chromosomes. This finding was unexpected because although bub3 Δ cells have a higher rate of chromosome mis-segregation, they were not thought to maintain an aneuploid karyotype. We investigated whether the increased copy number of specific genes on these acquired chromosomes offered a benefit to Bub3-deficient cells. Our results revealed that several genes involved in chromosome segregation and cell cycle regulation prevented the gain of chromosomes upon Bub3-depletion, suggesting that these genes confer a survival advantage. Overall, our study demonstrates that cells lacking Bub3 selectively retain specific chromosomes to increase the copy number of genes that promote proper chromosome segregation.

Chromosomal abnormalities detected by chromosomal microarray analysis and pregnancy outcomes of 4211 fetuses with high-risk prenatal indications

With the gradual liberalization of the three-child policy and the development of assisted reproductive technology in China, the number of women with high-risk pregnancies is gradually increasing. In this study, 4211 fetuses who underwent chromosomal microarray analysis (CMA) with high-risk prenatal indications were analysed. The results showed that the overall prenatal detection rate of CMA was 11.4% (480/4211), with detection rates of 5.82% (245/4211) for abnormal chromosome numbers and 5.58% (235/4211) for copy number variants. Additionally, the detection rates of clinically significant copy number variants were 3.78% (159/4211) and 1.8% (76/4211) for variants of uncertain significance. The detection rates of fetal chromosomal abnormalities were 6.42% (30/467) for pregnant women with advanced maternal age (AMA), 6.01% (50/832) for high-risk maternal serum screening (MSS) results, 39.09% (224/573) with abnormal non-invasive prenatal testing (NIPT) results, 9.21% (127/1379) with abnormal ultrasound results, and 5.1% (49/960) for other indications. Follow-up results were available for 4211 patients, including 3677 (3677/4211, 87.32%) whose infants were normal after birth, 462 (462/4211, 10.97%) who terminated their pregnancy, 51 (51/4211, 1.21%) whose infants were abnormal after birth, and 21 (21/4211, 0.50%) who refused follow-up. The results of this study demonstrate significant variation in the diagnostic rate of chromosomal microarray analysis across different indications, providing valuable guidance for clinicians to assess the applicability of CMA technology in prenatal diagnosis.

Sperm penetration at the maturing metaphase I stage can trigger oocyte activation in a mouse model

Can spermatozoa penetrate maturing metaphase I (MI) oocytes, and render subsequent development following conventional IVF in a mouse model? ICR mice were used in this study. Metaphase II (MII) cumulus-oocyte complexes (COC) harvested 15 h after injection of human chorionic gonadotrophin (HCG) were used for IVF as the control group (Group 1). In the treatment group (Group 2), maturing MI COC harvested 7 h after HCG injection were used for IVF. Fertilization, pronuclear formation, cleavage, blastocyst formation, DNA methylation status, chromosome number and live birth rates were used to evaluate the developmental dynamics and competency of maturing MI oocytes following conventional IVF. Maturing MI COC were fertilized using conventional IVF, and sperm penetration at MI-telophase I triggered oocyte activation. Most embryos resulting from fertilized MI oocytes developed to blastocyst stage during preimplantation development, albeit a substantial proportion of them were triploids due to the absence of the second meiotic division. Some of the embryos derived from fertilization of maturing oocytes were able to implant and gave rise to full-term development. Maturing MI COC from follicles before ovulation could be used for mouse IVF, and fertilized MI oocytes had high potential for development. Healthy offspring can be generated from maturing MI COC following conventional IVF. MI COC may represent a valuable source of 'usable' biomaterial in assisted reproduction. However, many embryos derived from MI COC via IVF have abnormal chromosome numbers in the mouse model. The implications of these findings for human IVF remain to be investigated.

Expert consensus on the test development and preliminary implementation of whole genome sequencing for fetal structural abnormalities

Fetal structural anomalies and birth defects are primarily caused by genetic variants such as chromosomal number abnormalities, copy number variations (CNV), single nucleotide variants (SNV), and small insertions and deletions (indel). Whole-genome sequencing (WGS) based on next-generation sequencing (NGS) as an emerging technology for genetic disease diagnosis can detect the aforementioned types of variants. In recent years, high-depth WGS (> 30×) for prenatal diagnosis has also become available, and proved to be practical for unraveling the genetic etiology of fetal developmental abnormalities. To facilitate clinical practice, test development and preliminary implementation of WGS for diagnosing fetal structural anomalies, we have formulated a consensus over the application of WGS in prenatal diagnosis by compiling previously published consensuses, guidelines, and research findings to provide a guidance on data analysis, reporting recommendations, and consultation of prenatal WGS results.

The genetics and clinical outcomes in 151 cases of fetal growth restriction: A Chinese single-center study

ObjectiveTo determine the detection rate of chromosomal abnormalities and pregnancy outcomes in fetuses with intrauterine growth restriction.Study designA total of 151 fetal samples with intrauterine growth restriction were divided into the isolated fetal growth restriction (FGR) group, FGR group with structural malformation, and FGR group with non-structural malformation, according to ultrasound abnormalities. The enrolled patients were divided into an early onset FGR group (<32 weeks) and a late-onset FGR group (≥32 weeks). Chromosomal karyotype and microarray analyses were performed and pregnancy outcomes were monitored.ResultsThe karyotypes of 122 patients were analyzed. Four patients exhibited abnormal chromosome numbers or structures. Variations in copy number were detected in 151 cases; 19 cases were found to have chromosomal abnormalities, with a positivity rate of 12.6 %. There was one trisomy in 18 cases, one trisomy in 21 cases, eight pathogenic copy number variations (CNVs), and nine CNVs of unknown clinical significance. The detection rate of FGR combined with structural malformation was significantly higher than that of isolated FGR group. The detection rate of FGR with structural malformations was significantly higher than that with non-structural malformations. The positive detection rate in the FGR group was similar to that in the FGR group with non-structural malformations, with no statistical significance. Chromosomal abnormalities were detected in 17 patients with early onset FGR, with a positivity rate of 13.8 %. Two cases of chromosomal abnormalities were detected in the late-onset FGR group, with a positive rate of 7.1 %, with no statistical significance. A total of 151 fetuses with FGR were followed up for pregnancy outcomes, resulting in 36 cases of pregnancy termination and 13 cases of loss to follow-up. Among the 102 delivered fetuses, six exhibited delayed growth and development, one presented with hypospadias, and another failed the hearing screening. The remaining 94 fetuses demonstrated normal growth and development.ConclusionsThis study confirms the value of CNV detection in fetuses and dynamic ultrasound monitoring for fetuses with intrauterine growth restriction.

Impact of the presence and number of chromosomal abnormalities on the clinical outcome in Waldenström Macroglobulinemia: a monocentric experience.

The prognostic and predictive role of specific gene mutations in Waldenström Macroglobulinemia (WM) is well-ascertained whereas the clinical impact of chromosome aberrations is far less known. Recent work has provided initial evidence for an adverse prognostic impact of some aberrations, such as del(6q), while other studies suggest a possible relationship between some clinical features (e.g. advanced age and/or inflammatory status) and specific cytogenetic abnormalities. To add to the still limited knowledge on WM cytogenetics and its clinical implications, we herein report our experience in a cohort of WM patients across 23years. Based on our retrospective study, we found that abnormal karyotype was more represented in older patients and maintained a statistically significant independence from other molecular, clinical, and biological features related to WM. The presence and number of cytogenetic aberrations correlated with inferior overall and progression-free survival outcomes regardless of the type of single chromosome aberration. Our data suggests that the role of the altered karyotype deserves to be further clarified especially in elderly WM patients, in whom cytogenetic abnormalities and disease biology appear to be characterized by a higher degree of complexity.

The chromosomal characteristics of spontaneous abortion and its potential associated copy number variants and genes.

This study aimed to investigate the correlation between chromosomal abnormalities in spontaneous abortion with clinical features and seek copy number variations (CNVs) and genes that might be connected to spontaneous abortion. Over 7years, we used CNV-seq and STR analysis to study POCs, comparing chromosomal abnormalities with clinical features and identifying critical CNVs and genes associated with spontaneous abortion. Total chromosomal variants in the POCs were identified in 66.8% (2169/3247) of all cases, which included 45.2% (1467/3247) numerical abnormalities and 21.6% (702/3247) copy number variants (CNVs). Chromosome number abnormalities, especially aneuploidy abnormalities, were more pronounced in the group of mothers aged ≥ 35years, the early miscarriage group, and the chorionic villi group. We further analyzed 212 pathogenic and likely pathogenic CNVs in 146 POCs as well as identified 8 statistically significant SORs through comparison with both a healthy population and a group of non-spontaneously aborted fetuses. Our analysis suggests that these CNVs may play a crucial role in spontaneous abortion. Furthermore, by utilizing the RVIS score and MGI database, we identified 86 genes associated with spontaneous abortion, with particular emphasis on PARP6, ISLR, ULK3, FGFRL1, TBC1D14, SCRIB, and PLEC. We found variability in chromosomal abnormalities across clinical features, identifying eight crucial copy number variations (CNVs) and multiple key genes that may be linked to spontaneous abortion. This research enhances the comprehension of genetic factors contributing to spontaneous abortion.

Machine-learning analysis reveals an important role for negative selection in shaping cancer aneuploidy landscapes

BackgroundAneuploidy, an abnormal number of chromosomes within a cell, is a hallmark of cancer. Patterns of aneuploidy differ across cancers, yet are similar in cancers affecting closely related tissues. The selection pressures underlying aneuploidy patterns are not fully understood, hindering our understanding of cancer development and progression.ResultsHere, we apply interpretable machine learning methods to study tissue-selective aneuploidy patterns. We define 20 types of features corresponding to genomic attributes of chromosome-arms, normal tissues, primary tumors, and cancer cell lines (CCLs), and use them to model gains and losses of chromosome arms in 24 cancer types. To reveal the factors that shape the tissue-specific cancer aneuploidy landscapes, we interpret the machine learning models by estimating the relative contribution of each feature to the models. While confirming known drivers of positive selection, our quantitative analysis highlights the importance of negative selection for shaping aneuploidy landscapes. This is exemplified by tumor suppressor gene density being a better predictor of gain patterns than oncogene density, and vice versa for loss patterns. We also identify the importance of tissue-selective features and demonstrate them experimentally, revealing KLF5 as an important driver for chr13q gain in colon cancer. Further supporting an important role for negative selection in shaping the aneuploidy landscapes, we find compensation by paralogs to be among the top predictors of chromosome arm loss prevalence and demonstrate this relationship for one paralog interaction. Similar factors shape aneuploidy patterns in human CCLs, demonstrating their relevance for aneuploidy research.ConclusionsOur quantitative, interpretable machine learning models improve the understanding of the genomic properties that shape cancer aneuploidy landscapes.

Detection of cytogenetic abnormalities in multiple myeloma by using optical genome mapping

Multiple myeloma (MM) is a plasma cell neoplasm characterized by numerous chromosomal number and structural abnormalities, which are of great significance for risk stratification and response evaluation of MM patients. Optical genome mapping (OGM) is a novel technology that has the potential to resolve many of the issues and limitations associated with traditional cytogenetic methods. To date, the clinical utility of OGM has been validated in the fields of cancer, reproduction, and embryonic dysplasia, et al. In this study, we compared OGM to traditional techniques for the first time in five newly diagnosed MM patients, and evaluated the potential of OGM for detecting cytogenetic aberrations and its clinical application value in MM.

Polyploid Cancer Cell Models in Drosophila.

Cells with an abnormal number of chromosomes have been found in more than 90% of solid tumors, and among these, polyploidy accounts for about 40%. Polyploidized cells most often have duplicate centrosomes as well as genomes, and thus their mitosis tends to promote merotelic spindle attachments and chromosomal instability, which produces a variety of aneuploid daughter cells. Polyploid cells have been found highly resistant to various stress and anticancer therapies, such as radiation and mitogenic inhibitors. In other words, common cancer therapies kill proliferative diploid cells, which make up the majority of cancer tissues, while polyploid cells, which lurk in smaller numbers, may survive. The surviving polyploid cells, prompted by acute environmental changes, begin to mitose with chromosomal instability, leading to an explosion of genetic heterogeneity and a concomitant cell competition and adaptive evolution. The result is a recurrence of the cancer during which the tenacious cells that survived treatment express malignant traits. Although the presence of polyploid cells in cancer tissues has been observed for more than 150 years, the function and exact role of these cells in cancer progression has remained elusive. For this reason, there is currently no effective therapeutic treatment directed against polyploid cells. This is due in part to the lack of suitable experimental models, but recently several models have become available to study polyploid cells in vivo. We propose that the experimental models in Drosophila, for which genetic techniques are highly developed, could be very useful in deciphering mechanisms of polyploidy and its role in cancer progression.

Clinical Experience of Prenatal Chromosomal Microarray Analysis in 6159 Ultrasonically Abnormal Fetuses.

A single-center retrospective study of G-band karyotyping and chromosomal microarray analysis (CMA) for the invasive prenatal diagnosis of 6159 fetuses with ultrasound abnormalities was conducted. This study aimed to investigate the incidence rates of chromosomal abnormalities and pregnancy outcomes and postpartum clinical manifestations by long-term follow-up and to explore the correlation between different types of prenatal ultrasound abnormalities and pathogenic chromosomal abnormalities. The overall incidence of pathogenic chromosomal aberrations in fetuses with ultrasound abnormalities was 7.58% (467/6159), which comprised 41.7% (195/467) with chromosome number abnormalities, 57.6% (269/467) with pathogenic copy-number variations (pCNVs), and 0.64% (3/467) with uniparental disomy (UPD). In addition, 1.72% (106/6159) with likely pathogenic copy-number variations (lpCNVs) and 3.04% (187/6159) with variants of unknown significance (VOUS) were detected by CMA. Ultrasound abnormalities were categorized into structural anomalies and soft marker anomalies. The incidence rate of pathogenic and likely pathogenic chromosomal abnormalities was significantly higher among fetuses with structural anomalies than soft markers (11.13% vs 7.59%, p < 0.01). We retrospectively analyzed the prenatal genetic outcomes for a large cohort of fetuses with different types of ultrasound abnormalities. The present study showed that the chromosomal abnormality rate and clinical outcomes of fetuses with different types of ultrasound abnormalities varied greatly. Our data have important implications for prenatal genetic counseling for fetuses with different types of ultrasound abnormalities.

Establishment and characterization of a canine chondrosarcoma cell line: Mango

In the global progress of bone tumor research, established stable and long-lasting transgenic chondrosarcoma (CSA) cell lines are rare, mainly of murine and human origin, while the establishment of canine CSA cell lines has yet to be reported. This study established a canine CSA cell line to facilitate the basic clinical study of canine CSA. Fifty five cases of canine osteolytic disease were collected, and more than 10 bone tumor samples from dogs with typical clinical signs were used for primary cell culture. A cell line with stable passaging for more than 100 generations and mouse tumorigenic ability was successfully cultured. According to the clinical characteristics of the dog and the histopathological results of the primary tumor, CSA was diagnosed, and the CSA cell line was designated Mango. Immunohistochemical (IHC) results showed that the immunoreactivity of bone gamma-carboxyglutamate protein (BGLAP), secreted protein acidic and rich in cysteine (SPARC), alkaline phosphatase (ALPL), vimentin (VIM) and S100 were positive. However, the immunoreactivity of pan-cytokeratin (PCK), chromogranin A (CGA), and platelet endothelial cell adhesion molecule-1 (CD31) was negative. Immunofluorescence (IF) results showed that the protein expressions in the Mango cell line were consistent with the IHC identification of the primary tumor. The Mango cell line’s doubling time was 43.92 h, and the cell formation rate exceeded 20%. There were abnormal chromosome numbers, hetero staining with toluidine blue, and certain calcification abilities. It could be passaged stably and continuously without changing the cell morphology and characteristics. In vivo, the cells were successfully injected into the nude mice model with a tumorigenic rate of 100%. The immunophenotype of the xenograft tumor was consistent with that of the primary tumor. Therefore, we effectively established a canine CSA cell line. As a promising cell material, this cell line can be used to construct a tumor-bearing model conducive to the subsequent basic research of canine CSA. Moreover, because of its similarity to human CSA, the animal model of CSA is also indispensable for investigating human CSA.

Abstract P1169: BubR1 Regulates Cardiac Development Through CamkII In Vivo

Congenital heart defects (CHD), which represent the most common type of congenital defects, are found in 8 out of 1000 births each year in the US. Aneuploidy, defined as an abnormal number of chromosomes in a cell, is the largest contributor to CHD. Defects in mitotic regulators can promote aneuploidy. For instance, mutations in the mitotic checkpoint protein BubR1 can lead to mosaic variegated aneuploidy (MVA). MVA patients display varied phenotypes including growth deficiency and a shortened lifespan. In addition, some patients develop CHDs such as atrioventricular septal defects. To determine whether BubR1 regulates cardiac development we carried out timed matings to harvest heart tissue at various embryonic stages. We found that BubR1 expression dramatically increases in the mouse heart through embryonic development. We engineered a conditional BubR1 knockout mouse model using the Cre-lox system which allows for the generation of cardiac-specific BubR1 knockout animals when crossing this BubR1 fl/fl mice to Nkx2.5-cre mice, which mediates deletion of BubR1 beginning at E7.5. Interestingly, we did not observe any homozygous cardiac-specific BubR1 knockout mice in newborn litters, suggesting that loss of BubR1 in the developing heart is embryonic lethal (n = 120, P &lt; 0.01). We observed that deletion of BubR1 in the embryonic heart leads to cardiac malformations including the absence of trabeculations and reduction in the size of ventricles. Immunofluorescence studies reveal that cardiac-specific BubR1 knockout embryos have an increase in cell death as measured by the apoptosis marker cleaved-caspase 3. These embryos also show an increase in the apoptosis regulator CaMKII, whose upregulation has been previously tied to an increase in cardiomyocyte apoptosis. Therefore, we conclude that BubR1 suppresses the expression of CaMKII in the developing heart to regulate apoptosis during cardiogenesis. Taken together, our data suggest that BubR1 is a critical regulator for cardiac development in vivo , and its mutation or loss may contribute to the development of CHDs.

Chromosomal aberrations induced by Mitomycin C in canine lymphocytes

Chromosomal aberrations comprise an abnormal number of chromosomes as well as changes in the structure of the chromosomes. Aberrations in the structure of chromosomes, such as gaps and breaks in chromatids and chromosomes, acentric fragments, telomeric associations, deletions, early chromatid-separation and large scale effects, such as pulverized metaphases, and sticky metaphases. In this study, the effect of Mitomycin C, a recognized clastogen on human lymphocytes, was assayed in cultures of canine lymphocytes, an animal species that is flourishing in comparative medicine. Blood cultures were performed on samples from a male and a female dog. Cytotoxicity using the mitotic index and genotoxicity testing were performed with 0.25 µg/ml Mitomycin C. The total chromosomal aberrations were significantly higher due to the effect of Mitomycin C (P=0.0247). The number of chromatid breaks nearly quintupled, while pulverized metaphases were found to be six times more frequent, and endoduplicated cells were three times higher than in negative control cultures. The quantitatively most relevant chromosomal aberration was the presence of sticky metaphases, related to adverse effects in chromatin proteins. The potential use of canine lymphocytes for chromosomal aberration assay is emphasized in the evaluation or re-evaluation of the genotoxic in vitro effect of xenobiotics, to evidence chromosomal damage.

Analysis of potential copy-number variations and genes associated with first-trimester missed abortion

BackgroundCopy number variation sequencing (CNV-seq) was proven to be a highly effective tool in studying of chromosomal copy number variations (CNVs) in prenatal diagnosis and post-natal cases with developmental abnormalities. However, the overall characteristics of missed abortion (MA) CNVs were largely unexplored. MethodsWe retrospectively analyzed the results of CNV-seq in first-trimester MA. The samples included were single pregnancy loss before 13 gestational weeks, and other potential factors affecting embryonic implantation and development had been excluded. Gene ontology and KEGG enrichment analysis was performed on the smallest overlapping regions (SORs) of high-frequency deletion/duplication. ResultOn the basis of strict inclusion and exclusion criteria, only 152 samples were included in our study. 77 (50.7%) samples displayed chromosome number abnormalities, 32 (21%) showed isolated CNVs, and 43 (28.3%) showed no CNVs. A total of 45 CNVs, ranging in size between 300 Kb and 126.56 Mb were identified, comprising 13 segmental aneuploidies CNVs, and 32 submicroscopic CNVs. Among these CNVs, we screened out four SORs (5q31.3, 5p15.33-p15.2, 8p23.3-p23.2, and 8q22.2–24.3), which were potentially associated with first-term MA. 16 genes were identified as potential miscarriage candidate genes through gene-prioritization analysis, including three genes (MYOM2, SDHA and TPPP) critical for embryonic heart or brain development. ConclusionWe identified some potential candidate CNVs and genes associated with first-trimester MA. 5q31.3 duplications, 5p15.33-p15.2 deletions, 8p23.3-p23.2 deletions and 8p22.2-p24.3 duplications are four potential candidate CNVs. Additionally, MYOM2, SDHA and TPPP are potential genes associated with first-trimester MA.

Colchicine Effect of Mitosis Root Tip by Banana Kepok Yellow (Musa paradisiaca L.) Polyploid Explants

Colchicine can inhibit spindle formation so that doubled chromosomes fail to separate during anaphase cytologically to induce mutations that produce polyploid plants. Yellow kepok banana is a triploid banana. The supply of yellow kepok bananas is hampered by conventional cultivation methods and the limited availability of quality seeds. This study aims to determine the effect of adding colchicine compound to tissue culture media on the mitotic index, chromosome number, and chromosomal abnormalities in yellow kepok bananas and the formation of polyploid plantlets. This study was included in the experimental study by conducting mitotic preparation and observing morphology after the test sample was induced by colchicine. The results of the research that has been done show that the addition of the compound colchicine to the tissue culture medium of yellow kepok banana causes a decrease in the mitotic index, an increase in the number of chromosomes, the presence of chromosomal abnormalities, the formation of polyploid plantlets, and an increase in the number of roots, but there is a reduction in root length.

O-064 Genome-wide analysis of meiotic recombination reveals a subset of oocytes with reduced frequency of recombination and increased risk of aneuploidy.

Abstract Study question Are there differences in recombination rates between male and female embryos, and is the frequency of recombination associated with the risk of aneuploidy? Summary answer There is more recombination in female meiosis than in males. Aneuploidy is associated with fewer recombination events. Genome-wide reduction in recombination predisposes oocytes to aneuploidy. What is known already Aneuploidy is believed to be the primary explanation for embryo implantation failure and miscarriage and is, therefore, of great relevance to IVF. Despite the high frequency and clinical importance of aneuploidy, the mechanisms causing a gamete to become chromosomally abnormal are only partially understood. One factor known to influence the risk of aneuploidy is meiotic recombination. An absence of recombination or atypical positioning of chiasmata predisposes to chromosomal malsegregation. Most data on the subject of meiotic recombination and aneuploidy comes from miscarriages and aneuploid births, but this provides an incomplete view since most aneuploidies are lethal at earlier developmental stages. Study design, size, duration ∼300,000 polymorphisms scattered across the genome were genotyped in DNA from 125 couples and 543 blastocysts that they produced. The inheritance of individual alleles was tracked from parents to embryos, allowing the parental origin of each chromosome to be determined. This strategy also permitted the detection of abnormal numbers of chromosomes, allowed deduction of which meiotic division aneuploidy had arisen in, and revealed the sites of meiotic recombination on each chromosome in the embryos analysed. Participants/materials, setting, methods Embryo analysis involved trophectoderm biopsy, followed by multiple displacement amplification. Parental DNA and amplified embryo samples were then tested using a microarray. 22,133 individual recombination events on 14,561 chromatids were evaluated. The relationship between aneuploidy and recombination frequency was considered. The average distance between recombination events was calculated by dividing the size of each autosome (in Mega bases – Mb) by the number of detected recombination events. An unpaired t-test was conducted for statistical analysis. Main results and the role of chance A quarter of all embryos were found to carry one or more chromosome abnormalities (altogether, 221 chromosome abnormalities were detected). Of these, 82% had a maternal (oocyte) origin, while 18% were paternal. Chromosomes 16 and 22 were the most frequently affected by aneuploidy, together accounting for 33% of all maternal chromosome abnormalities. Analysis of recombination events in maternally and paternally inherited chromosomes confirmed that female meiosis is associated with a significantly higher frequency of recombination (41.4 ±7.7 recombination events compared with 24.4±4 in chromosomes of paternal origin). Chromosomes 21 and 22 showed the lowest number of recombination events, consistent with their small size (average of 0.6 and 0.7 recombination sites per chromosome, respectively). As expected, a complete failure of recombination occurred more frequently for chromosomes with lower numbers of recombination events. Interestingly, embryos with aneuploidies of maternal origin showed evidence that the oocytes that produced them had lower recombination rates in general (not restricted to the affected chromosomes) than those producing euploid embryos (P = 0.01). Across the genome, average distances between recombination events were ∼10% lower for euploid embryos compared with aneuploid embryos (72.4 +/-14 Mb versus 81+-18 Mb) (P = 0.0004). Limitations, reasons for caution It is possible that the pattern and frequency of recombination sites that exist in sperm and oocytes might show some differences from the blastocysts tested during this study, considering that more than half of all oocytes either fail to fertilise or produce embryos that arrest before the blastocyst stage. Wider implications of the findings As expected, a higher aneuploidy rate and more recombination events were seen in female meiosis compared with male meiosis. Interestingly, aneuploidy was associated with lower levels of recombination across the whole genome, not only for the affected chromosomes, suggesting that unusually low recombination activity predisposes some oocytes to chromosome malsegregation. Trial registration number not applicable

Molecular genetic analysis of 1,980cases of male infertility.

The present study aimed to investigate the occurrence of chromosomal karyotype abnormalities and azoospermia factor (AZF) microdeletion on the long arm of the Y chromosome (Yq) in infertile men, and to determine their association with infertility to ultimately improve clinical outcomes in these patients. A total of 1,980 azoospermic and oligospermic men from the outpatient department of the Fujian Maternity and Child Health Hospital (Fuzhou, China) were recruited between January 2016 and December 2019. Peripheral blood was used for karyotype analysis; AZF microdeletion analysis of the Yq was performed using capillary electrophoresis. Among the 1,980 patients, 178 had chromosomal abnormalities (9.0%; 178/1,980), of whom 98 had an abnormal number of chromosomes. Among the abnormal karyotypes, the most common was 47, XXY (80/178; 44.9%). AZF microdeletion on the Yq occurred at a rate of 10.66% (211/1,980); the most common type was the AZFb/c deletion (sY1192; 140/211; 66.4%). The present findings showed that karyotype abnormalities and AZF gene microdeletion are important drivers of male infertility. Specifically, men with Yqh- and del(Y)(q11) had a higher risk of AZF microdeletion. These results suggested that patient treatment could be personalized based on routine molecular genetic analysis, which could further alleviate the economic and emotional burden of undergoing redundant or ineffective treatments.

Abstract 1214: Establishment and characterization of reversibly immortalized endometrial and ovarian epithelial cell lines using Sendai virus

Abstract Objective: We aimed to establish reversibly immortalized cell lines from human uterine and ovary cells using the Sendai virus (SeV) vector. The immortalized cells derive from normal and benign ovarian epithelial cells and endometrial epithelial cells. Furthermore, we sought to elucidate the mechanisms of carcinogenesis using the immortalized cell lines. Methods: Cells were collected at the time of surgery after obtaining patient consent. The cells used in this study were as follows: ovarian epithelial cells (normal epithelium, Ov n; normal epithelium with germline BRCA1 or BRCA2 mutation, Ov BRCA1 2; ovarian endometrioma, Ov endo; mucinous cystadenoma; Ov m), normal fallopian tube (FT) cells, and endometrial epithelium (normal epithelium, Em n). These cells were infected with temperature-sensitive SeV vectors carrying three immortalization genes, Bmi-1, hTERT, and SV40T.The presence of infection was confirmed through Green Fluorescent Protein (GFP) and Orange Fluorescent Protein (OFP). Immunoreactivity to the anti-human EpCAM antibody (a marker derived from epithelial carcinoma) in each SeV-infected cell was confirmed through flow cytometry. QH and multicolor FISH staining were performed for karyotyping of metaphase chromosomes in each cell line to determine chromosome number and structural abnormalities. Human transcriptome sequencing analysis was performed with NovaSeq 6000 (Illumina) using total RNA from each cell line. Some genes that showed significant expression in each cell line were subjected to real-time PCR (RT-PCR). Results: We established the immortalized cell lines from human uterine and ovarian tissues. SeV-infected cells exhibited GFP and OFP fluorescence, while non-infected cells did not. SeV infection allowed all primary cell lines to grow for 25 or more passages, while non-infected SeV cells lacked the proliferative capacity and showed senescence-like morphology. SeV-infected cells senesced in a temperature-dependent manner. Ov n SeV- infected cells ion causedshowed a small increase in chromosome structural abnormalities. But, Ov BRCA1 and 2 SeV-infected cells showed larger than thatand . Llong-term passaged cells did not show immune response to anti-human EpCAM antibodies in normal cells. Eleven Three genes were predominantly expressed in Ov BRCA1 and Ov BRCA2 cells and were not expressed in Ov n cells. SomeTwo out of ththe three genesem were found to be predominantly expressed in Ov endo cells compared to the expression in the Ovn cell line. Furthermore, RT-PCR results also indicated substantially higher expression of two genes in Ov BRCA1/2 cells and in Ov endo cells compared to the expression in Ov n cells. Conclusion: We succeeded in the reversible immortalization of endometrial and ovarian epithelial cells by using SeV infection. We identified several candidate genes that may be involved in the oncogenic mechanism of ovarian cancer associated with endometriosis or germline BRCA1 and BRCA2. Citation Format: Masayo Okawa, Hiroaki Komatsu, Kohei Hikino, Yuki Iida, Masayo Hosokawa, Mayumi Sawada, Akiko Kudoh, Jun Chikumi, Shinya Sato, Genki Hichiwa, Yasuhiro Kazuki, Kanako Kazuki, Fuminori Taniguchi, Mitsuo Oshimura, Tasuku Harada. Establishment and characterization of reversibly immortalized endometrial and ovarian epithelial cell lines using Sendai virus [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1214.