Incidence Of Chromosome Aneuploidy Research Articles

Analysis of genetic etiology and related factors in 1 065 women with spontaneous abortions

To explore the genetic etiology and related factors in 1 065 women with spontaneous abortions. All patients have presented at the Center of Prenatal Diagnosis of Nanjing Drum Tower Hospital from January 2018 to December 2021. Chorionic villi and fetal skin samples were collected, and the genomic DNA was assayed by chromosomal microarray analysis (CMA). For 10 couples with recurrent spontaneous abortions but normal CMA results for abortive tissues, non-in vitro fertilization-embryo transfer (IVF-ET) pregnancies and no previous history of live births and no structural abnormalities of the uterus, peripheral venous blood samples were collected. Genomic DNA was subjected to trio-whole exome sequencing (trio-WES). Candidate variants were verified by Sanger sequencing and bioinformatics analysis. Multifactorial unconditional logistic regression analysis was carried out to analyze the factors that may affect chromosomal abnormality in spontaneous abortions, such as the age of the couple, number of previous spontaneous abortions, IVF-ET pregnancy and history of live birth. The incidence of chromosomal aneuploidies in spontaneous abortions during the first trimester was compared in young or advanced-aged patients by chi-square test for liner trend. Among the 1 065 spontaneous abortion patients, 570 cases (53.5%) of chromosomal abnormalities were detected in spontaneous abortion tissues, which included 489 cases (45.9%) of chromosomal aneuploidies and 36 cases (3.4%) of pathogenic/likely pathogenic copy number variations (CNVs). Trio-WES results have revealed one homozygote variant and one compound heterozygote variants in two pedigrees, both of which were inherited from the parents. One likely pathogenic variant was detected in the patient from two pedigrees. Multifactorial unconditional Logistic regression analysis suggested that age of patient was an independent risk factor of chromosome abnormalities (OR = 1.122, 95%CI: 1.069-1.177, P < 0.001), the number of previous abortions and IVF-ET pregnancy were independent protective factors for chromosomal abnormalities (OR = 0.791, 0.648; 95%CI: 0.682-0.916, 0.500-0.840; P = 0.002, 0.001), whilst the age of husband and history of live birth were not (P > 0.05). The incidence of aneuploidies in the abortive tissues has decreased with the number of previous spontaneous abortions in young patients (χ² = 18.051, P < 0.001), but was not significantly correlated with the number of previous spontaneous abortions in advanced-aged patients with spontaneous abortions (P > 0.05). Chromosomal aneuploidy is the main genetic factor for spontaneous abortion, though CNVs and genetic variants may also underlie its genetic etiology. The age of patients, number of previous abortions and IVF-ET pregnancy are closely associated with chromosome abnormalities in abortive tissues.

Incidence and origin of meiotic whole and segmental chromosomal aneuploidies detected by karyomapping.

What is the incidence and origin of meiotic whole and segmental aneuploidies detected by karyomapping at a blastocyst stage in human-derived IVF embryos? What is the distribution of various types of errors, including rare chromosomal abnormalities? The incidence of chromosomal aneuploidies was assessed in 967 trophectoderm biopsies from 180 couples who underwent 215 cycles of IVF with preimplantation genetic testing for monogenetic disease with a known causal mutation with a mean maternal age of 32.7 years. DNA from both parents and a reference sample was genotyped together with the analysed trophectoderm samples by karyomapping (single-nucleotide-polymorphism-based array). Chromosomal abnormalities were detected in 31% of the analysed samples. At least one whole chromosomal aneuploidy was detected in 27.1% of the trophectoderm biopsies, whereas a segmental aneuploidy was detected in 5.1% of the trophectoderm biopsies. Our results reveal that segmental aneuploidies predominantly affect paternally derived chromosomes (70.4%; P < 0.01) compared with whole chromosomal aneuploidies that more frequently affect maternally derived chromosomes (90.1%; P < 0.0001). Also, the frequency of meiosis I (MI) and meiosis II (MII) errors was established in meiotic trisomies; MI errors were observed to be more frequent (n = 102/147 [69.4%]) than MII errors (n = 45/147 [30.6%]). Karyomapping is a robust method that is suitable for preimplantation genetic testing for monogenetic disease and for detecting meiotic aneuploidies, including meiotic segmental aneuploidies, and provides complex information about their parental origin. Our results revealed that segmental aneuploidy more frequently affects paternal chromosomes compared with whole chromosomal aneuploidy in human IVF embryos at the blastocyst stage.

Destabilization of spindle assembly checkpoint causes aneuploidy during meiosis II in murine post-ovulatory aged oocytes

Mammalian oocyte quality degrades over time after ovulation in vitro, which can cause fatal defects such as chromosomal aneuploidy. As various oocyte manipulations employed in assisted reproductive technology are time consuming, post-ovulatory aging is a serious problem to overcome in reproductive medicine or ova research. In this study, we investigated the effects of postovulatory aging on the incidence of chromosome aneuploidy during meiosis II, with a focus on the expression of functional proteins from the spindle assembly checkpoint (SAC). Chromosome analysis was used to assess the rate of aneuploidy in in vitro aged oocytes, or in early embryos derived from aged oocytes. Immunofluorescent staining was used to detect the localization of MAD2, which is a SAC signal that monitors the correct segregation of sister chromatids. Immunoblotting was used to quantify cohesin subunits, which are adhesion factors connecting sister chromatids at the metaphase II (MII) centromere. It was shown that post-ovulatory oocyte aging inhibits MAD2 localization to the sister kinetochore. Furthermore, oocyte aging prevented cohesin subunits from being maintained or degraded at the appropriate time. These data suggest that the destabilization of SAC signaling causes sister chromatid segregation errors in MII oocytes, and consequently increases the incidence of aneuploidy in early embryos. Our findings have provided distinct evidence that the post-ovulatory aging of oocytes might also be a risk factor for aneuploidy, irrespective of maternal age.

Incidence of chromosomal aneuploidies at embryonic level with comparison based on type of biopsy and maternal age: first indian experience

Incidence of chromosomal aneuploidies at embryonic level with comparison based on type of biopsy and maternal age: first indian experience

An altered endometrial CD8 tissue resident memory T cell population in recurrent miscarriage

When trying to conceive 1% of couples have recurrent miscarriages, defined as three or more consecutive pregnancy losses. This is not accounted for by the known incidence of chromosomal aneuploidy in miscarriage, and it has been suggested that there is an immunological aetiology. The endometrial mucosa is populated by a variety of immune cells which in addition to providing host pathogen immunity must facilitate pregnancy. Here we characterise the endometrial CD8-T cell population during the embryonic window of implantation and find that the majority of cells are tissue resident memory T cells with high levels of CD69 and CD103 expression, proteins that prevent cells egress. We demonstrate that unexplained recurrent miscarriage is associated with significantly decreased expression of the T-cell co-receptor CD8 and tissue residency marker CD69. These cells differ from those found in control women, with less expression of CD127 indicating a lack of homeostatic cell control through IL-7 signalling. Nevertheless this population is resident in the endometrium of women who have RM, more than three months after the last miscarriage, indicating that the memory CD8-T cell population is altered in RM patients. This is the first evidence of a differing pre-pregnancy phenotype in endometrial immune cells in RM.

Study of the Sperm Chromosomal Aneuploidies of Isolated Teratozoospermic Men

Objective To determine whether patients with isolated teratozoospermia have increased or decreased incidence of chromosomal aneuploidies. Methods Sperm obtained from isolated teratozoospermic men (teratozoospermic group, n=18) and normal fertile men (the control, n=5) were analyzed using FISH (for chromosomes 18, X and Y). Results A total of 58 178 spermatozoa were counted from the teratozoospermia group and 16 369 spermatozoa were counted from the control, with the hybridization rates of 97.5% and 98.3%, respectively. The major types of chromosomal aneuploidies were disomy (YY18, XX18, XY18, Y1818 and X1818) and diploidy (1818XX, 1818YY, 1818XY). In the teratozoospermic group and the control, the disomy rates of 18 chromosome were 0.29 ± 0.16% and 0.03 ± 0.02%, the disomy rates of sex chromosome were 0.65 ± 0.24% and 0.05 ± 0.02%, the diploidy rates were 0.14 ± 0.12% and 0.04 ± 0.03%, respectively. All the differences between these two groups were significant (P Conclusions Sperm of isolated teratozoospermic men have higher rates of 18, X and Y chromosomal aneuploidies than that of the fertile controls.

The assosiation between preimplantation embryo morphology and the incidence of chromosome aneuploidy

OBJECTIVE: To evaluate the association between preimplantation embryo morphology and proportion of aneuploidy on day 3 and 4 after oocyte retrieval. DESIGN: Retrospective analysis. MATERIALS AND METHODS: Preimplantation genetic screening (PGS) was performed in 64 IVF cycles of 58 patients because of history of repeated pregnancy loss, repeated implantation failure and advanced maternal age. The chromosomes 13, 16, 18, 21, X and Y were assessed in blastomeres biopysed from day 3 embryos by fluorescence in situ hybridization (FISH). A total of 614 embryos were analyzed. The incidence of chromosome aneuploidy was compared depending on the cell number, cellular fragment, and blastomere evenness of embryos. Data were analyzed by chi-square analysis. RESULTS: One hundred seventy-nine embryos (29.2%) were chromosomally normal and the others were aneuploid for one or more chromosomes. The incidence of aneuploidy was lower in normal-cleaving embryos (7- ∼ 9-cell stage) compared to slow-cleaving (≤ 6-cell stage) or fast-cleaving embryos (≥ 10-cell stage) at day 3 after oocytes retrieval. The incidence of aneuploidy was significantly higher (P<0.001) in slow-cleaving embryos (79.2%) than normal-cleaving embryos (62.0%). Aneuploidy of fast-cleaving embryos (78.6%) was higher than normal-cleaving embryos but there was no significant difference. The incidence of aneuploidy was significantly lower in normal-cleaving embryos (compaction ∼ morula stage, 58.9%) compared to arrested embryos (≤6-cell stage, 82.1%) or slow-cleaving embryos (7- ∼ 9-cell stage, 75.6%) at day 4 after oocytes retrieval. Aneuplody of moderately slow-cleaving embryos (10- ∼ 14-cell stage, 64.9%) was higher than normal-cleaving embryos but there was no significant. The incidence of chromosome aneuploidy was significantly increased (P<0.01) in embryos with cellular fragments more than 25% of embryo compared to embryos with cellular fragment less than 25% of embryo. Embryo with uneven blastomeres (73.7%) had a higher proportion of chromosome aneuploidy compared to those with even blastomeres (62.3%; P<0.01). CONCLUSIONS: The proportion of chromosome aneuploidy was significantly higher in slow-cleaving embryos compared to normal-cleaving embryos at day 3 and day4, respectively. The increase of cellular fragment and uneven blastomeres were associated with an increased incidence of chromosome abnormalities.

Evaluation of aneuploidy frequency for chromosomes 6 and 17 in eyelid tumours using the FISH technique

Although basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) are very common skin tumours, the incidence of chromosome aneuploidy with regard to the eyelid has not been investigated. We aimed to find the frequency of chromosome 6 and 17 aneuploidies in eyelid tumours' interphase nuclei with fluorescence in situ hybridization (I-FISH) with chromosome specific DNA probes. I-FISH with chromosome 6 and 17 centromere specific DNA probes was used in the eyelids of 10 patients with BCC or SCC and the peripheral blood cells of 10 healthy donors as controls. The frequency of chromosome 6 and 17 aneuploidies was significantly higher in 7 out of 10 patients and 5 out of 10 patients, respectively, than in controls, indicating a higher frequency of aneuploidy in BCC than in SCC of the eyelid. Distribution of hybridization signals for chromosome 6 and 17 was wide ranging, indicating heterogeneity of cell populations with aneuploidy between patients. These findings indicate that acquisition of chromosome aneuploidies in eyelid tumours may have an important pathogenic role in both BCC and SCC of the eyelid area.

P-29: Impact of Maternal Age on Rate of Chromosomal Aneuploidy in Women Undergoing In Vitro Fertilization and Preimplantation Genetic Diagnosis

Objective: To examine the influence of maternal age on the incidence of chromosomal aneuploidy in women undergoing in vitro fertilization (IVF) and preimplantation genetic diagnosis for aneuploidy screen (PGD-AS) for chromosomes 13, 18, 21, X and Y.

Sequential multiple probe fluorescence in-situ hybridization analysis of human oocytes and polar bodies by combining centromeric labelling and whole chromosome painting.

The incidence of chromosomal aneuploidy was analysed in 104 unfertilized human oocytes and 56 first polar bodies using a double-label fluorescence in-situ hybridization (FISH) procedure. Combinations of centromeric (or locus-specific) DNA probes and whole chromosome painting probes for chromosomes 9, 13, 16, 18, 21 and X were applied on oocyte preparations, in a sequential FISH protocol. This combined approach allowed a precise in-situ identification of both chromosomes and free chromatids, and consequently a reliable analysis of chromosomal segregation errors. Of the 104 analysed oocytes, 84 (80.7%) displayed a normal chromosome constitution. Three cases of chromosome non-disjunction (2.8%) were found, whereas seven oocytes (6.7%) presented extra single chromatids. In addition, 12 oocytes (11.5%) showed balanced pre-division of one pair of sister chromatids. Although this phenomenon was not classified as aneuploidy, it could lead to aneuploidy at anaphase II. Abnormalities were observed in all the targetted chromosomes. The present data confirm that both whole chromosome non-disjunction and premature chromatid separation constitute the two major mechanisms of aneuploidy in human female meiosis.

Statistically significant correlation between normal sperm morphology (NSM) and sperm binding potential to an immobilized monolayer of hyaluronan using the HYDAK(r) sperm hyaluronan-binding assay (HBA)

Objectives: Hyaluronan, a high molecular weight glycosaminoglycan, is a major constituent of the cumulus oophorous matrix surrounding the human oocyte. During the process of fertilization, hyaluronan may play a critical role in the selection of functionally competent sperm. Huszar has demonstrated that specific motile sperm attach to a monolayer of hyaluronan immobilized on a surface and that such bound sperm demonstrate specific parameters of developmental maturity. Hyaluronan-bound (HB) sperm exhibit decreased levels of both cytoplasmic inclusions and residual histones, an increased expression of the HspA2 chaperone protein, and a marked reduction in the incidence of chromosomal aneuploidy. The relationship between HB sperm and enhanced levels of developmental maturity led to the current study of sperm binding potential and morphology. A pilot study was undertaken to explore the potential correlation between the ability of a seminal population to bind to the hyaluronan substrate and the Kruger Strict Criteria (KSC) morphological assessment demonstrated by the same population. Design: Excess semen samples from 31 infertility patients were assayed in the HYDAK(r) HBA chambers. Both normal and male factor patients were included. All specimens were analyzed for percent NSM using KSC. Two independent technicians performed each evaluation. Materials and Methods: Specimen collection, analysis and disposal followed a protocol approved by the Hospital Institutional Review Board. Hydak(r) HBA chambers, supplied by Biocoat, Inc., were fabricated from Cell-Vu(r) dual chamber disposable sperm counting slides. A molecular layer of hyaluronan was covalently bound to one chamber while the second counting chamber remained unmodified and served as a control. Following a 10-minute incubation period, the number of total, free motile and bound motile sperm were scored in each chamber. The HBA score was calculated as # bound motile sperm / # total motile sperm. Three morphology slides were prepared per patient and a minimum of 300 sperm were assessed using a 100X oil immersion lens and a calibrated reticle. A two-way contingency table evaluating the variables of NSM and HB was constructed to evaluate the data. Significance was tested by the Pearson Chi-squared statistic using SPSS for Windows software. Results: The analysis showed that fluctuations in NSM were statistically related to the ability of sperm to bind to hyaluronan (Chi squared = 8.16, p = 0.007, n = 31). Seminal populations demonstrating a NSM of <4% carried a mean HBA score of 44.4% (n = 13). In contrast, seminal populations carrying a NSM of >4% demonstrated a mean HBA score of 71.5% (n = 18). Conclusions: Hyaluronan may play a critical role in the selection of functionally competent sperm during in vivo fertilization. The current study demonstrated that a statistically significant relationship existed between the HBA and NSM carried by a seminal population. A seminal population carrying a higher HBA score was concomitant with increased levels of NSM. A lower HBA score was also found to be statistically consistent with poor morphology parameters. The HYDAK(r) HBA may therefore serve as a valuable diagnostic tool in assessing the level of developmental maturity, incidence of aneuploidy and morphological parameters of a seminal population. Ongoing studies are exploring the role hyaluronan may play in the selection of functionally competent sperm and the potential value of the HBA as a diagnostic tool.

Chromosomal FISH analysis of unfertilized human oocytes and polar bodies.

The incidence of chromosomal aneuploidy was studied in 208 unfertilized metaphase II human oocytes from an in vitro fertilization program by fluorescence in situ hybridization using probes for chromosomes 18, 21, and X. Chromosome spreads were prepared by a gradual fixation-air-drying method. We obtained analyzable results from 183 oocytes and 93 polar bodies; 167 oocytes (91%) were normal, 11 (6%) were diploid, and 5 (3%) were aneuploid. Of the five aneuploid oocytes, four involved chromosome 21, and one involved the X chromosome. In this study, oocyte aneuploidy caused by both nondisjunction of bivalent chromosomes and predivision of univalent chromosomes was observed. The aneuploidy rate (9.8%) in the oocytes from women aged >==35 years was significantly higher than that (0.7%) in those aged 23 to 34 years ( P = 0.0017).

Role of mitotic control in spermatogenesis

Objective: To study the correlation between the incidence of sex chromosome aneuploidies in the somatic cells and spermatozoa in karyotypically normal infertile men and fertile donors. Design: A prospective, phase two, controlled study. Setting: A teaching Hospital Reproductive Medicine and Medical Genetics Units. Patient(s): Ten patients with idiopathic oligozoospermia and 10 sperm donors with proven fertility, all with a normal karyotype 46,XY. Intervention(s): Multicolor fluorescence in situ hybridization (FISH) of peripheral blood lymphocytes and spermatozoa using a probe cocktail containing the alpha satellite DXZ1 for the X centromere, DYZ1 for the heterochromatic region of the long arm of the Y, and cosmids D21S259, D21S341, and D21S342 for Down syndrome critical region of chromosome 21. Main Outcome Measure(s): The incidence of chromosome X, Y, and 21 aneuploidies in peripheral lymphocytes and spermatozoa in both groups. Result(s): The incidence of aneuploidies related to chromosomes X, Y, and 21 were significantly higher in peripheral lymphocytes and spermatozoa of infertile men compared with donors. There was a positive correlation between the incidence of chromosome aneuploidies in the somatic cells and sperm in all men. Conclusion(s): These findings provide suggestive evidence for the importance of mitosis in spermatogenesis and the role of mitotic instability in unexplained oligozoospermia.

Does the Color of Amniotic Fluid Still Matter?

Second trimester amniotic fluid (AF) is generally clear or very light yellow. We examined the color of 2,141 AF samples. Fifty-six specimens were brown, 35 were green. There were 71 samples with abnormal karyotype (3.46%). In the group with brown AF, there were 7 abnormal karyotypes out of 56 (12.5%). There was 1 case of aneuploidy out of the 35 green samples (2.86%). We conclude that green AF in the second trimester, absent any other findings, carries no special significance, but brown AF carries a fourfold increased incidence of chromosomal aneuploidy in patients undergoing genetic amniocentesis.

Aging and aneuploidy in human oocytes and follicular cells.

The incidence of chromosomal aneuploidy in the oocyte and surrounding follicular cells in women of different ages was investigated. Oocytes and granulosa cells derived from ovarian specimens from a random population of 289 adult patients ages 16 to 76 years undergoing gynecologic surgery for nonovarian pathology were cultured for short periods, and cytogenetic preparations were scored for chromosome number and morphology. Of 91 oocytes harvested at second meiotic metaphase, five oocytes revealed a chromosomal abnormality. Cytogenetic analysis of the granulosa cells revealed aneuploid cells as well as complements with structural changes. A significant difference between the percentage of granulosa cell aneuploidy in the 25 to 34 years group and all other age groups was found, suggesting a decrease of the tendency for granulosa cells to exhibit aneuploidy in older age groups. Previous reports of aneuploidy in human ovary and other somatic cell types suggest that follicular cells behave differently in their response to aging. There also would appear to be a difference between the chromosomal response of oocytes and granulosa cells to aging.

Effect of maternal parity on aneuploidy in early mouse embryos.

An attempt to evaluate the incidence of chromosomal aneuploidy in mouse blastocysts recovered from females of various ages and parity levels revealed an insignificant regression coefficient for aneuploidy on age of the female and its square, and an insignificant correlation coefficient for aneuploidy with the number of previous offspring born to the dam. However, significant regression coefficients were obtained for aneuploidy on parity of the dam and its square. These results indicate that not only does aneuploidy increase with parity level, but the rate of increase accelerates as parity level increases. Possible explanations for the increase in aneuploidy and its detrimental effect on reproductive efficiency were discussed.