Maintaining genomic stability is crucial for normal development. At earlier stages of preimplantation development, as the embryonic genome activation is not fully completed, the embryos may be more prone to abnormalities. Aneuploidies are one of the most common genetic causes of implantation failure or first-trimester miscarriages. Apoptosis is a crucial mechanism to eliminate damaged or abnormal cells from the organism to enable healthy growth. Therefore, this study aimed to determine the relationship between the expression levels of genes involved in apoptosis in human aneuploid and euploid blastocysts. In total, 32 human embryos obtained from 21 patients were used for this study. Trophectoderm biopsies were performed and next-generation screening was carried out for aneuploidy screening. Total RNA was extracted from each blastocyst separately and cDNA was synthesized. Gene expression levels were evaluated using RT-PCR. The statistical analysis was performed to evaluate the gene expression level variations in the euploid and aneuploid embryos, respectively. The expression level of the BAX gene was significantly different between the aneuploid and euploid samples. BAX expression levels were found to be 1.5-fold lower in aneuploid cells. However, the expression levels of BAK and MAD2L1 genes were similar in each group. This study aimed to investigate the possible role of genes involved in apoptosis and aneuploidy mechanisms. The findings of this investigation revealed that the BAX gene was expressed significantly differently between aneuploid and euploid embryos. Therefore, it is possible that the genes involved in the apoptotic pathway have a role in the aneuploidy mechanism.

The aim of our study was to evaluate the correlation between sperm quality and ploidy status of the derived blastocysts. We performed a retrospective analysis on a restricted pool of patients enrolling only those who had no female factors. Male patients with genetic factors affecting spermatogenesis were also excluded. We chose a maternal age ≤38 years to decrease the female factor, therefore the male factor was the main component of sterility. We divided the patients in four groups based on semen quality and comparing fertilization, pregnancy and euploidy rates above all. In total, 201 intracytoplasmic sperm injection (ICSI) cycles were enrolled in the study. Cycles were divided into four groups, according to semen source: normal semen, oligoasthenoteratozoospermia (OAT), cryptospermia or non-obstructive azoospermia (NOA). An extremely statistically lower fertilization rate was found in NOA patients. Unexpectedly, no differences were detected in blastocyst formation, euploidy, aneuploidy and mosaicism rates among the four groups. Interestingly, we also found a higher abortion rate comparing NOA to normal semen with an odds ratio of 4.67. In our study no statistically significant differences among the analyzed groups were found, showing little or no effect at all using spermatozoa from different semen sources or quality. This may be linked to the oocyte competence of fixing sperm DNA damage and it could be hypothesized that only sperm with a good rate of DNA integrity are able to fertilize the oocyte, explaining why poor quality semen is reflected in a low fertilization rate without effect on ploidy.

The objective of this study is to compare aneuploidy rates between three distinct areas of the human trophectoderm: mural, polar and a region in between these two locations termed the ‘mid’ trophectoderm. This is a cohort study on in vitro fertilization (IVF) patients undergoing comprehensive chromosome screening at the blastocyst stage at a private IVF clinic. All embryos underwent assisted hatching on day 3 with blastocyst biopsy and comprehensive chromosome screening. Biopsied blastocysts were divided into three groups depending on which area (polar, mid, or mural) of the trophectoderm was protruding from the zona pellucida and biopsied. Aneuploidy rates were significantly higher with cells from the polar region of the trophectoderm (56.2%) compared with cells removed from the mural region of the trophectoderm (30.0%; P = 0.0243). A comparison of all three areas combined also showed a decreasing trend, but this did not reach clinical significance, polar (56.2%), mid (47.4%) and mural trophectoderm (30.0%; P = 0.1859). The non-concordance demonstrated between polar and mural trophectoderm can be attributed to biological occurrences including chromosomal mosaicism or procedural differences between embryologists.

Shortly after the implementation of comprehensive chromosome screening (CCS) techniques for preimplantation genetic testing for aneuploidies (PGT-A), the discussion about the transition from day 3 to blastocyst stage biopsy was initiated. Trophectoderm biopsy with CCS is meant to overcome the limitations of cleavage-stage biopsy and single-cell analysis. The aim of this study was to assess the results obtained in our PGT-A programme after the implementation of this new strategy. Comparisons between the results obtained in 179 PGT-A cycles with day 3 biopsy (D+3) and fresh embryo transfer, and 204 cycles with trophectoderm biopsy and deferred (frozen–thawed) embryo transfer were established. Fewer embryos were biopsied and a higher euploidy rate was observed in the trophectoderm biopsy group. No differences in implantation (50.3% vs. 61.4%) and clinical pregnancy rate per transfer (56.1% vs. 65.3%) were found. Although the mean number of euploid embryos per cycle did not differ between groups (1.5 ± 1.7 vs. 1.7 ± 1.8), the final number of euploid blastocysts available for transfer per cycle was significantly higher in the trophectoderm biopsy group (1.1 ± 1.3 vs. 1.7 ± 1.8). This factor led to an increased cumulative live birth rate in this last group (34.1% vs. 44.6%). Although both strategies can offer good results, trophectoderm biopsy offers a more robust diagnosis and the intervention is less harmful for the embryos so more euploid blastocysts are finally available for transfer and/or vitrification.

Berry syndrome is a rare CHD. Approximately 29 cases have been described in the literature. Surgical correction has been successfully performed as well. We report the case of a newborn diagnosed with Berry syndrome who was subsequently diagnosed with trisomy 13. Cytogenetic analysis should be performed before surgical repair for optimal management.

The aim of our study was to analyse chromosomal aneuploidy occurence in rabbit oocytes and embryos. Chromosomal analysis was done in rabbit oocytes and rabbit preimplantation embryos at 2-, 4- and 8-cell stages derived from in vivo fertilization. For mitotic cycle synchronization at the metaphase stage, 2-, 4- and 8-cell embryos were incubated in k-DMEM medium, supplemented with colcemid (1 μg/ml), for 7, 12 or 13h respectively. Success of metaphase synchronization was at values of 100, 86.1 and 92.2% for 2-, 4- and 8-cell embryos respectively. Recovery rate of analysable metaphase plates was reached at 58.8%, 83.9% and 59.8% for 2-, 4- and 8-cell embryos and 100% for oocytes. Significant difference (p < 0.01) in aneuploidy rate between oocytes (40.7%) and 2-cell embryos (62.5%) was found. These results demonstrate higher efficiency of synchronization of embryo cells at the metaphase stage, what may contribute to elevating the proportion of analysable nuclei.

New cytogenetical data are provided for the three Ranunculus species occurring on Iles Kerguelen. Chromosome morphometrical analysis (idiograms) strongly argues for a relationship between them, with some indications of a more recent origin for R. moseleyi. Aneuploidy was found within the three species for the first time. Whilst only a slight aneuploidy exists in R. pseudotrullifolius and R. moseleyi, R. biternatus shows a tendency to hyperaneuploidy. Vegetative reproduction is likely to increase the number of plants showing such chromosome number irregularities. Aneuploidy could explain some of the differences between the species in ecological tolerance and distributional area.

Aneuploidy has been previously reported in wild and cultivated Pacific oysters, Crassostrea gigas, and has been shown to be negatively correlated with growth. This is especially important since high variability of growth rate is one of the major problems in the aquacultural production of this species. The existence of a genetic basis for the observed differences in aneuploidy was first investigated through the comparative study of six full-sib families, with mean individual weights ranging from 0.59 to 1.49 g. The slowest growing family was found to have the highest level of aneuploidy. Significant differences in aneuploidy were also found among families when individuals with the same growth rate were sampled. This supports the hypothesis of the existence of a genetic basis for the control of aneuploidy level. Additionally, the possible inheritance of the level of aneuploidy was studied in four full-sib progenies originating from crosses within and between two different populations with contrasting levels of aneuploidy. The limited number of parental oysters (N = 6) in which the scoring of aneuploidy was possible did not allow demonstration of the inheritance of the level of aneuploidy. However, a genetic difference in aneuploidy could be attributed to the origin of the parental populations. As in the first experiment, significant differences in aneuploidy were observed between progenies when sampling individuals of the same weight. Thus, the results of our study of full-sib progenies of C. gigas lend support to the hypothesis of a genetic basis for the level of aneuploidy.

Alterations in the rate of oocyte meiotic maturation (OM) and the timing of the metaphase-anaphase transition may predispose oocytes to premature centromere separation (PCS) and aneuploidy. Tamoxifen has the potential for perturbing the rate of OM since it can function as a calcium antagonist by binding to calmodulin and inhibiting the formation of a calcium-calmodulin complex which is needed for activating calmodulin-dependent cAMP phosphodiesterase and initiating OM. The objective of this study was to test the hypothesis that tamoxifen alters the rate of OM and predisposes oocytes to PCS and aneuploidy. Different does of tamoxifen were administered by oral gavage to female mice preovulation. Metaphase II oocyte and 1-cell zygote chromosomes were C-banded and cytogenetically analysed. Tamoxifen treatment resulted in a modest, but significant (p < 0.05), increase in oocytes with PCS. Similar frequencies of hyperploidy and oocytes with unpaired, single chromatids (SC) were found. Metaphase I, diploid and premature anaphase (PA) oocytes were not detected. Hyperploidy, polyploidy, PCS, PA and SC were not detected in zygotes. These data indicate that the levels of tamoxifen-induced PCS found in mouse oocytes did not predispose zygotes to aneuploidy. Tamoxifen did, however, reduce the proportion of females exhibiting oestrus.

The frequency of aneuploid sperm was assessed by fluorescence in situ hybridisation (FISH) in a 47,XYY male previously studied by sperm karyotyping. A total of 20 021 sperm were studied: 10 017 by two-colour FISH for chromosomes 13 and 21 and 10 002 by three-colour FISH for the sex chromosomes using chromosome 1 as an autosomal control for diploidy and lack of hybridisation. Results were compared with more than 500 000 sperm from 18 normal men. The frequencies of X-bearing (49.4%) and Y-bearing sperm (49.8%) were not significantly different from 50% as shown in our sperm karyotyping study. There was no significant increase in the frequency of diploid sperm compared with control donors. There was a significant increase in the frequency of disomy for chromosome 13 (p<0.0001) and XY disomy (p=0.0008) compared with control donors. However, since the frequency of disomy was 0.40% for chromosome 13 and 0.55% for XY disomy, it is not surprising that these increases were not discovered previously in our analysis of 75 sperm karyotypes. Our results suggest that the extra Y chromosome is eliminated during spermatogenesis in the majority of cells but that there may be a small but significant increase in the frequency of aneuploid sperm in these men.