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Popovic M, Dhaenens L, Boel A, Menten B, Heindryckx B. Chromosomal mosaicism in human blastocysts: the ultimate diagnostic dilemma. Hum Reprod Update 2020; 26:313-334. [DOI: 10.1093/humupd/dmz050] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 11/29/2019] [Indexed: 12/30/2022] Open
Abstract
Abstract
BACKGROUND
Trophectoderm (TE) biopsy and next generation sequencing (NGS) are currently the preferred techniques for preimplantation genetic testing for aneuploidies (PGT-A). Although this approach delivered important improvements over previous testing strategies, increased sensitivity has also prompted a rise in diagnoses of uncertain clinical significance. This includes reports of chromosomal mosaicism, suggesting the presence of karyotypically distinct cells within a single TE biopsy. Given that PGT-A relies on the chromosomal constitution of the biopsied cells being representative of the entire embryo, the prevalence and clinical implications of blastocyst mosaicism continue to generate considerable controversy.
OBJECTIVE AND RATIONALE
The objective of this review was to evaluate existing scientific evidence regarding the prevalence and impact of chromosomal mosaicism in human blastocysts. We discuss insights from a biological, technical and clinical perspective to examine the implications of this diagnostic dilemma for PGT-A.
SEARCH METHODS
The PubMed and Google Scholar databases were used to search peer-reviewed publications using the following terms: ‘chromosomal mosaicism’, ‘human’, ‘embryo’, ‘blastocyst’, ‘implantation’, ‘next generation sequencing’ and ‘clinical management’ in combination with other keywords related to the subject area. Relevant articles in the English language, published until October 2019 were critically discussed.
OUTCOMES
Chromosomal mosaicism predominately results from errors in mitosis following fertilization. Although it appears to be less pervasive at later developmental stages, establishing the true prevalence of mosaicism in human blastocysts remains exceedingly challenging. In a clinical context, blastocyst mosaicism can only be reported based on a single TE biopsy and has been ascribed to 2–13% of embryos tested using NGS. Conversely, data from NGS studies disaggregating whole embryos suggests that mosaicism may be present in up to ~50% of blastocysts. However, differences in testing and reporting strategies, analysis platforms and the number of cells sampled inherently overshadow current data, while added uncertainties emanate from technical artefacts. Moreover, laboratory factors and aspects of in vitro culture generate further variability. Outcome data following the transfer of blastocysts diagnosed as mosaic remain limited. Current studies suggest that the transfer of putative mosaic embryos may lead to healthy live births, but also results in significantly reduced ongoing pregnancy rates compared to the transfer of euploid blastocysts. Observations that a subset of mosaic blastocysts has the capacity to develop normally have sparked discussions regarding the ability of embryos to self-correct. However, there is currently no direct evidence to support this assumption. Nevertheless, the exclusion of mosaic blastocysts results in fewer embryos available for transfer, which may inevitably compromise treatment outcomes.
WIDER IMPLICATIONS
Chromosomal mosaicism in human blastocysts remains a perpetual diagnostic and clinical dilemma in the context of PGT-A. This review offers an important scientific resource, informing about the challenges, risks and value of diagnosing mosaicism. Elucidating these uncertainties will ultimately pave the way towards improved clinical and patient management.
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Affiliation(s)
- Mina Popovic
- Ghent-Fertility and Stem Cell Team (G-FAST), Department for Reproductive Medicine, Ghent University Hospital, Corneel Heymanslaan 10, 9000 Ghent, Belgium
| | - Lien Dhaenens
- Ghent-Fertility and Stem Cell Team (G-FAST), Department for Reproductive Medicine, Ghent University Hospital, Corneel Heymanslaan 10, 9000 Ghent, Belgium
| | - Annekatrien Boel
- Ghent-Fertility and Stem Cell Team (G-FAST), Department for Reproductive Medicine, Ghent University Hospital, Corneel Heymanslaan 10, 9000 Ghent, Belgium
| | - Björn Menten
- Center for Medical Genetics, Ghent University Hospital, 9000 Ghent, Belgium
| | - Björn Heindryckx
- Ghent-Fertility and Stem Cell Team (G-FAST), Department for Reproductive Medicine, Ghent University Hospital, Corneel Heymanslaan 10, 9000 Ghent, Belgium
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Abstract
During the 1970s, domestic animal biotechnology, i.e., embryo transfer in farm animals, was confronted with the problem of embryonic developmental arrest observed in vitro, especially during the cycle in which maternal to zygotic transition (MZT) cycle takes place. In farm animals, obtaining blastocysts is mandatory, as transfer at earlier stages results in expulsion of the embryo from the vagina. In humans, the first attempts to obtain blastocysts with classical culture media were disappointing, and the use of a coculture strategy was naturally tempting: the first significant results of successful blastocyst development were obtained in the early 1980s, using trophoblastic tissue as a feeder layer in order to mimic an autocrine embryotrophic system. The next supporting cell systems were based on oviduct epithelial cells and uterine cells in order to achieve a paracrine effect. Non-hormone dependence was then demonstrated with the use of prepubertal cells, and finally with the use of established cell lines of nongenital origin (African Green Monkey Kidney, Vero cells). The embryotrophic properties are linked to features of "transport epithelia." Vero cells have been extensively used in human ART, and most of our knowledge about the human blastocyst was gathered with the use of this technology. Coculture is still in current use, but with systems that employ autologous uterine cells. Results following the use of this technology in human ART are superior to those observed with the use of sequential media. The benefit is linked to the release of free radical scavengers and growth factors by the feeder cells. In animal biotechnology, an important part of the "precious embryos," i.e., those resulting from cloning technology, involves coculture with buffalo rat liver (BRL) cells or Vero cells.
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van Echten-Arends J, Mastenbroek S, Sikkema-Raddatz B, Korevaar JC, Heineman MJ, van der Veen F, Repping S. Chromosomal mosaicism in human preimplantation embryos: a systematic review. Hum Reprod Update 2011; 17:620-7. [DOI: 10.1093/humupd/dmr014] [Citation(s) in RCA: 198] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Sabhnani TV, Elaimi A, Sultan H, Alduraihem A, Serhal P, Harper JC. Increased incidence of mosaicism detected by FISH in murine blastocyst cultured in vitro. Reprod Biomed Online 2011; 22:621-31. [PMID: 21530405 DOI: 10.1016/j.rbmo.2011.01.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Revised: 01/23/2011] [Accepted: 01/25/2011] [Indexed: 11/19/2022]
Abstract
The majority of in-vitro-derived human preimplantation embryos are chromosomally abnormal but whether the same pattern exists in vivo is unknown. This would be impossible to demonstrate in humans. Hence we chose murine embryos to study this difference owing to their ease of manipulation and compared the incidence of mosaicism between in-vivo- and in-vitro-cultured embryos. Two groups of embryos were analysed. Group A (in vitro) were obtained 48h following superovulation and cultured in vitro until the blastocyst stage. Fluorescent in-situ hybridization (FISH) was performed at different stages that included the cleavage, morula and blastocyst stage. Group B (in vivo) were obtained on day 2 or day 5 and FISH was performed immediately without culture. There was an increase in chromosomal mosaicism seen from the cleavage stage up to the blastocyst stage in the in-vitro culture group. Overall chromosomal abnormality from day 3 to day 5 was found to be 30% (28/94) in group A. The incidence of chromosomal abnormalities in blastocysts from group B was significantly lower than group A blastocysts (8% (3/40) and 31% (20/64) respectively; P<0.05). These data show that in-vitro cultured embryos had a significantly higher incidence of mosaicisim in comparison with the in-vivo group. Cultured human embryos show high levels of chromosomal abnormalities but whether this is a pattern seen in all embryos or is the result of culture is unknown. To study this pattern we used mouse embryos and carried out chromosome analysis by fluorescent in-situ hybridization. We compared embryos that were cultured (in vitro) with those that were not (in vivo, i.e. grown exclusively in the mouse). We found that cultured embryos showed significantly higher chromosomal abnormalities as compared with in vivo embryos. This suggests that certain culture conditions are responsible for the high level of chromosomal abnormalities seen in these embryos, which should be investigated further.
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Affiliation(s)
- Tanya V Sabhnani
- Centre for Reproductive and Genetic Health, University College London Hospital, London, UK.
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Johnson DS, Cinnioglu C, Ross R, Filby A, Gemelos G, Hill M, Ryan A, Smotrich D, Rabinowitz M, Murray MJ. Comprehensive analysis of karyotypic mosaicism between trophectoderm and inner cell mass. Mol Hum Reprod 2010; 16:944-9. [PMID: 20643877 PMCID: PMC2989828 DOI: 10.1093/molehr/gaq062] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Aneuploidy has been well-documented in blastocyst embryos, but prior studies have been limited in scale and/or lack mechanistic data. We previously reported preclinical validation of microarray 24-chromosome preimplantation genetic screening in a 24-h protocol. The method diagnoses chromosome copy number, structural chromosome aberrations, parental source of aneuploidy and distinguishes certain meiotic from mitotic errors. In this study, our objective was to examine aneuploidy in human blastocysts and determine correspondence of karyotypes between trophectoderm (TE) and inner cell mass (ICM). We disaggregated 51 blastocysts from 17 couples into ICM and one or two TE fractions. The average maternal age was 31. Next, we ran 24-chromosome microarray molecular karyotyping on all of the samples, and then performed a retrospective analysis of the data. The average per-chromosome confidence was 99.95%. Approximately 80% of blastocysts were euploid. The majority of aneuploid embryos were simple aneuploid, i.e. one or two whole-chromosome imbalances. Structural chromosome aberrations, which are common in cleavage stage embryos, occurred in only three blastocysts (5.8%). All TE biopsies derived from the same embryos were concordant. Forty-nine of 51 (96.1%) ICM samples were concordant with TE biopsies derived from the same embryos. Discordance between TE and ICM occurred only in the two embryos with structural chromosome aberration. We conclude that TE karyotype is an excellent predictor of ICM karyotype. Discordance between TE and ICM occurred only in embryos with structural chromosome aberrations.
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Affiliation(s)
- D S Johnson
- Gene Security Network, Inc., 2686 Middlefield Road, Suite C, Redwood City, CA 94063, USA.
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Huang J, Lian Y, Qiao J, Chen Y, Ren X, Liu P. Characteristics of embryo development in Robertsonian translocations' preimplantation genetic diagnosis cycles. Prenat Diagn 2010; 29:1167-70. [PMID: 19813217 DOI: 10.1002/pd.2376] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE To explore the embryo development characteristics in Robertsonian translocations (RTs) in their preimplantation genetic diagnosis (PGD) cycles. METHOD A total of 37 RT carrier couples underwent 41 blastomere PGD cycles from August 2005 to September 2008. The development of 272 embryos was analyzed in their PGD cycles. RESULT(S) At D3, there were 161 high-grade embryos, including 59 normal/balanced embryos and 102 abnormal embryos. There was no difference between the normal/balanced embryo group and the abnormal embryo group in terms of the high-grade embryo percentage (64.84% vs 56.35%, p = 0.179). However, at D5-D6, the blastocyst percentage in the normal/balanced embryo group was significantly higher than that in the abnormal embryo group (43.96% vs 20.44%, p = 0.000). CONCLUSION(S) Normal/balanced embryos developed better and a self-selective mechanism may exist in the RTs' embryos at the blastocyst formation stage.
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Affiliation(s)
- Jin Huang
- Reproductive Medicine Center, Peking University Third Hospital, Beijing 100191, China
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Coppola G, Alexander B, Di Berardino D, St John E, Basrur PK, King WA. Use of cross-species in-situ hybridization (ZOO-FISH) to assess chromosome abnormalities in day-6 in-vivo- or in-vitro-produced sheep embryos. Chromosome Res 2007; 15:399-408. [PMID: 17429747 DOI: 10.1007/s10577-007-1125-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2006] [Revised: 01/30/2007] [Accepted: 01/30/2007] [Indexed: 11/29/2022]
Abstract
Causes of chromosomal differences such as mosaicism between embryos developed in vivo and in vitro may be resolved using animal models to compare embryos generated in vivo with those generated by different production systems. The aims of this study were: (1) to test a ZOO-FISH approach (using bovine painting probes) to detect abnormal chromosome make-up in the sheep embryo model, and (2) to examine the extent of chromosome deviation in sheep embryos derived in vivo and in vitro. Cytogenetic analysis was performed on day 6 in-vivo and in-vitro derived sheep embryos using commercially available bovine chromosome painting probes for sex chromosomes X-Y and autosomes 1-29. A total of 8631 interphase and metaphase nuclei were analyzed from 49 in-vitro-derived and 51 in-vivo-derived embryos. The extent of deviation from normal ovine chromosome make-up was higher (p < 0.05) in in-vitro-produced embryos relative to in-vivo-derived embryos (65.3% vs. 19.6% respectively) mainly due to diploid-polyploid mosaicism. Polyploid cells ranged from 3n to 8 n with tetraploids most predominant among non-diploid cells. The proportions of polyploid cells per mixoploid embryo in in-vitro-produced embryos ranged from 1.4% to 30.3%, in contrast to less than 10% among the in-vivo-derived embryos. It was concluded that in-vitro-derived embryos are vulnerable to ploidy change compared to their in-vivo counterparts. The application of ZOO-FISH to domestic animal embryos is an effective approach to study the chromosome complement of species for which DNA probes are unavailable.
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Affiliation(s)
- Gianfranco Coppola
- Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Ontario, Canada, N1G 2W1
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Coulam CB, Jeyendran RS, Fiddler M, Pergament E. Discordance among blastomeres renders preimplantation genetic diagnosis for aneuploidy ineffective. J Assist Reprod Genet 2007; 24:37-41. [PMID: 17216564 PMCID: PMC3455087 DOI: 10.1007/s10815-006-9073-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2006] [Accepted: 09/07/2006] [Indexed: 10/23/2022] Open
Abstract
PURPOSE To investigate the contribution of discordance among blastomeres from the same embryo in the interpretation of blastomeres biopsied from day 3 embryos. METHODS 228 IVF embryos had two blastomeres removed and fluorescent in situ hybridization (FISH) was used to detect aneuploidy of chromosomes 13, 15, 16, 18, 21, 22, X and Y. Of the 228 embryos, 102 had complete FISH results for both blastomeres. RESULTS When the 2 blastomeres of 102 embryos with successful FISH results were compared, 26 (25.5%) were concordant for all 8 chromosomes and 76 (74.5%) were discordant for one or more chromosomes. Among the 102 embryos, 12 (12%) were disomy in both blastomeres and 37 (36%) were disomic in all 8 chromosomes in one of the two blastomeres. CONCLUSION Discordance among blastomeres from the same embryo appears to present a significant problem in interpreting results of embryos biopsied on day 3 and analyzed by FISH especially when most PGD's are done on single blastomeres.
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Affiliation(s)
- C B Coulam
- Pregnancy Success Center, Rinehart Center for Reproductive Medicine, 233 East Erie St, Suite 500, Chicago, IL 60611, USA.
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Baltaci V, Satiroglu H, Kabukçu C, Unsal E, Aydinuraz B, Uner O, Aktas Y, Cetinkaya E, Turhan F, Aktan A. Relationship between embryo quality and aneuploidies. Reprod Biomed Online 2006; 12:77-82. [PMID: 16454940 DOI: 10.1016/s1472-6483(10)60984-4] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Many high-grade embryos selected for transfer according to their morphological evaluation were detected to have chromosomal abnormalities after aneuploidy screening for infertility by preimplantation genetic diagnosis (PGD). The aim of this study was to detect if there is any correlation between embryo quality and genetic status. The chromosomal status of the day three embryos was studied by multicolour fluorescence in-situ hybridization for chromosomes 13, 18, 21, X and Y. PGD was performed on 132 patients for 1107 embryos. The correlation between embryo quality and aneuploidy was analysed. The analysis showed that a large proportion of normal embryos (50.7%, n = 280) were grade I. In addition, a considerably high proportion of aneuploid embryos (36.1%, n = 83) were evaluated as grade I. There was a significant relationship between PGD results and embryo grades (P = 0.001). Of the 69 polyploid embryos, 21.7% were grade I and 37.8% were grade II. Of the 83 haploid embryos, 27.8% were grade I and 34.9% were grade II. Euploidy was positively related to morphological grade of embryo (P = 0.001). It was also possible for chromosomally abnormal embryos to have a good developmental potential, and they could be selected for embryo transfer unless the PGD procedure was applied.
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Affiliation(s)
- V Baltaci
- GenArt Women's Health and Reproductive Biotechnology Centre, Cinnah Street 47/A Cankaya, Ankara, Turkey.
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Cooper ML, Darilek S, Wun WS, Angus SC, Mensing DE, Pursley AN, Dunn RC, Grunert GM, Cheung SW. A retrospective study of preimplantation embryos diagnosed with monosomy by fluorescence in situ hybridization (FISH). Cytogenet Genome Res 2006; 114:359-66. [PMID: 16954679 DOI: 10.1159/000094226] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2006] [Accepted: 04/18/2006] [Indexed: 11/19/2022] Open
Abstract
This report is a retrospective study of preimplantation embryos diagnosed with monosomy for chromosomes 13, 15, 16, 18, 21, 22, X and Y on day 3 to determine the rate of true positives, false positives and/or mosaicism and to assess if these embryos are suitable for in vitro fertilization (IVF) transfer. In a one year period, 80 patients went through preimplantation genetic diagnosis for aneuploidy screening (PGD-AS). Monosomy was diagnosed in 51 embryos. Fluorescence in situ hybridization (FISH) was then performed on the blastomeres at day 5-7 with commercially available probes using the same probe set that initially identified monosomy for chromosomes 13, 16, 21 and 22 or chromosomes 15, 18, X and Y. Based on FISH analysis, the monosomy diagnosed during routine PGD-AS analysis was confirmed in 17 of the 51 embryos. A euploid result for the specific chromosomes tested was observed in 16 of the 51 embryos while mosaicism was found in the remaining 18 embryos. This results in an estimated false positive rate of 3.8% for a diagnosis of monosomy. Reanalysis of these embryos demonstrates that the majority of monosomy diagnoses represents true monosomy or mosaicism and should be excluded for transfer in IVF. Furthermore, improved understanding from recent emerging data regarding the fate of oocytes in women with advanced maternal age undergoing IVF to the development of early embryos may provide a valuable insight into the mechanism of chromosome mosaicism.
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Affiliation(s)
- M L Cooper
- Baylor College of Medicine, Houston, TX 77030, USA
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Munné S, Velilla E, Colls P, Garcia Bermudez M, Vemuri MC, Steuerwald N, Garrisi J, Cohen J. Self-correction of chromosomally abnormal embryos in culture and implications for stem cell production. Fertil Steril 2006; 84:1328-34. [PMID: 16275225 DOI: 10.1016/j.fertnstert.2005.06.025] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2005] [Revised: 06/30/2005] [Accepted: 06/30/2005] [Indexed: 12/22/2022]
Abstract
OBJECTIVE To ascertain whether embryos classified by preimplantation genetic diagnosis (PGD) for infertility as abnormal and then plated to obtain stem cells would self-correct partially or totally in culture, producing disomic stem cells. DESIGN Prospective study to determine the chromosome status of embryos on day 3 and 6, as well as cultured cells derived from inner cell masses from the same embryos when cultured up to day 12. SETTING Research laboratory. PATIENT(S) Patients undergoing PGD of aneuploidy. INTERVENTION(S) Of 142 embryos classified by PGD for aneuploidy as abnormal, 50 were cultured to the blastocyst stage. At that stage a fraction of the embryos underwent trophectoderm biopsy to reconfirm the PGD diagnosis. After further co-culture with feeders up to day 12, 34 embryos attached to the feeder cells. Of those, 24 were analyzed by fluorescence in situ hybridization (FISH) and the rest for the expression of Oct-4, SSEA-3, SSEA-4, TRA1-60, and TRA1-80. MAIN OUTCOME MEASURE(S) Disomic cells obtained from trisomic embryos. RESULT(S) Analysis by FISH of day-12 cultures showed that 7 were totally normal, 6 were mostly abnormal, and 11 had experienced some chromosome normalization, having between 21% and 88% normal cells. Day-12 culture was positive for Oct-4 expression by reverse transcriptase polymerase chain reaction analysis and for SSEA-3, SSEA-4, TRA1-60, and TRA1-80 by immunocytochemistry. CONCLUSION(S) Chromosome self-normalization occurs in a significant proportion of chromosomally abnormal embryos, possibly because of the loss of a chromosome in trisomic cells after blastocyst stage. Thus chromosomally abnormal embryos are a potential source of disomic stem cells. Not all chromosomally abnormal embryos self-corrected. Abnormal stem cells that might be derived could be used as models to study the effect of chromosomal abnormalities on human development.
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Munné S. Chromosome abnormalities and their relationship to morphology and development of human embryos. Reprod Biomed Online 2006; 12:234-53. [PMID: 16478592 DOI: 10.1016/s1472-6483(10)60866-8] [Citation(s) in RCA: 185] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
This review covers the relationship between chromosome abnormalities, morphological abnormalities and embryonic development. The baseline of chromosome abnormalities in human embryos produced by assisted reproduction is higher than 50%, regardless of maternal age. While aneuploidy increases with maternal age, abnormalities arising post-meiotically, such as mosaicism, chaoticism, polyploidy and haploidy, have similar incidence in all age groups (about 33%). Post-meiotic abnormalities do increase with dysmorphism. The most common dysmorphisms found in cleavage-stage embryos are multinucleation, fragmentation and uneven cells, among others. All dysmorphisms are associated with an increase in post-meiotic chromosome abnormalities and a decreased implantation potential. Similarly, embryos developing slowly or with arrested development have higher incidence of post-meiotic abnormalities than normally developing ones. Chromosome studies in blastocysts indicate that mosaicism is the most common abnormality but that the load of abnormal cells decreases with increasing blastocyst quality. Regardless of blastocyst quality, more than 40% of mosaics are still chromosomally abnormal and will not implant or will spontaneously abort. Because aneuploidy is not related to cleavage stage dysmorphism and trisomies can reach blastocyst stage and beyond, morphological analysis is not enough to select against chromosome abnormalities, and thus preimplantation genetic diagnosis should be recommended in patients 35 and older.
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Li M, DeUgarte CM, Surrey M, Danzer H, DeCherney A, Hill DL. Fluorescence in situ hybridization reanalysis of day-6 human blastocysts diagnosed with aneuploidy on day 3. Fertil Steril 2005; 84:1395-400. [PMID: 16275234 DOI: 10.1016/j.fertnstert.2005.04.068] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2004] [Revised: 04/25/2005] [Accepted: 04/25/2005] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To determine the concordance of day-6 blastocyst analysis with the day-3 fluorescence in situ hybridization (FISH) aneuploidy diagnosis. DESIGN Retrospective study. SETTING In vitro fertilization laboratory. PATIENT(S) Six hundred sixty embryos were included from 94 IVF/intracytoplasmic sperm injection patients undergoing preimplantation genetic diagnosis. INTERVENTION(S) None. MAIN OUTCOME MEASURE(S) Single blastomeres biopsied on day 3. Aneuploidy screening for chromosomes 13, 18, 21, X, and Y were analyzed. Left-over blastocysts were reanalyzed on day 6. RESULT(S) Among the 660 embryos evaluated, 367 (55.6%) were euploid and 281 (42.6%) were aneuploid. Of the euploid embryos, 213 embryos were transferred, 68 were frozen on day 5, and 86 were left. All 281 aneuploid embryos were further cultured, and 55 (19.6%) progressed to blastocysts. When FISH reanalysis was performed, 33 of 55 blastocysts (60%) were confirmed aneuploid in concordance with the day-3 diagnosis. However, 22 of 55 blastocysts (40%) were determined to be euploid. In addition, 207 aneuploid embryos (73.7%) arrested before day 6, as opposed to 32 of the 86 euploid embryos (37.2%). CONCLUSION(S) Day-3 single-cell embryo biopsy reveals that aneuploidy can be confirmed in 60.7% of the blastocysts on reanalysis. The majority of discordance is most likely due to embryo mosaicism and possibly a limited ability to "self-correct."
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Affiliation(s)
- Man Li
- ART Reproductive Center, Beverly Hills, California 90210, USA.
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Baart EB, Martini E, van den Berg I, Macklon NS, Galjaard RJH, Fauser BCJM, Van Opstal D. Preimplantation genetic screening reveals a high incidence of aneuploidy and mosaicism in embryos from young women undergoing IVF. Hum Reprod 2005; 21:223-33. [PMID: 16155075 DOI: 10.1093/humrep/dei291] [Citation(s) in RCA: 207] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND In order to assess the frequency of aneuploidy and mosaicism in embryos obtained from IVF patients aged <38 years, preimplantation genetic screening (PGS) was performed after biopsy of two blastomeres. Furthermore, the reliability of this diagnosis was assessed by performing reanalysis of the embryo on day 5. METHOD The copy numbers of 10 chromosomes (1, 7, 13, 15, 16, 18, 21, 22, X and Y) were investigated by fluorescence in situ hybridization (FISH) analysis. Embryos that were found to be abnormal or of insufficient morphological quality were cultured until day 5 and reanalysed. Results obtained were compared to the day 3 blastomere analysis. RESULTS After analysis of 196 embryos (one cell in 38% and two cells in 62%), only 36% of the embryos were found to be normal on day 3. After analysis of two blastomeres, 50% showed chromosomal mosaicism. Comparison of the FISH results from day 3 blastomeres and day 5 embryos yielded an overall cytogenetic confirmation rate of 54%. CONCLUSIONS The rates of mosaicism and aneuploidy in these embryos from young IVF patients are similar to those published for older women. We found the best confirmation rate after a diagnosis based on two cells, where both blastomeres showed the same chromosomal abnormality. In contrast, after a mosaic diagnosis the confirmation rate was low. The present study provides the first detailed reanalysis data of embryos analysed by PGS and clearly demonstrates the impact of mosaicism on the reliability of the PGS diagnosis.
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Affiliation(s)
- E B Baart
- Division of Reproductive Medicine, Department of Obstetrics and Gynaecology, Erasmus MC, University Medical Center, Dr. Molewaterplein 40, 3015 GD Rotterdam, The Netherlands.
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Daphnis DD, Delhanty JDA, Jerkovic S, Geyer J, Craft I, Harper JC. Detailed FISH analysis of day 5 human embryos reveals the mechanisms leading to mosaic aneuploidy. Hum Reprod 2005; 20:129-37. [PMID: 15567885 DOI: 10.1093/humrep/deh554] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Fluorescence in situ hybridization (FISH) analysis has shown that human embryos display a high level of chromosomal mosaicism at all preimplantation stages. The aim of this study was to investigate the mechanisms involved by the use of two probes for each of three autosomes at different loci and to determine the true level of aneuploid mosaicism by excluding FISH artefacts. METHODS Embryos were cultured in two different types of medium: group I were cultured in standard cleavage medium for up to day 5 and group II were cultured from day 3 to day 5 in blastocyst medium. Three rounds of FISH were performed. In round 1, the probes used were 1pTel, 11qTel and 18CEP; in round 2, the probes used were 1satII/III, 11CEP and 18qTel; in round 3, the probes used were 18CEP, XCEP and YCEP. RESULTS A total of 21 embryos were analysed in each group. The FISH results revealed one uniformly diploid and 20 mosaic embryos for group I, and two uniformly diploid and 19 mosaic embryos for group II. The predominant type of mosaicism was diploid/aneuploid. The use of two different probes per autosome was able to distinguish FISH artefacts affecting 5% of nuclei from true single cell anomalies. CONCLUSIONS Post-zygotic chromosome loss was the most common mechanism leading to aneuploidy mosaicism for both groups, followed by chromosome gain, with fewer examples of mitotic non-disjunction.
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Affiliation(s)
- D D Daphnis
- UCL Centre for Preimplantation Genetic Diagnosis, Department of Obstetrics and Gynaecology, University College London, 86-96 Chenies Mews, London, WC1E 6HX, UK
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Clouston HJ, Herbert M, Fenwick J, Murdoch AP, Wolstenholme J. Cytogenetic analysis of human blastocysts. Prenat Diagn 2002; 22:1143-52. [PMID: 12454974 DOI: 10.1002/pd.502] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
UNLABELLED The human blastocyst is key to understanding the aetiology of constitutional chromosome abnormalities in our species. OBJECTIVES To investigate the range and incidence of chromosome abnormalities in a large series of human blastocysts, using classic cytogenetic techniques. METHODS Using thymidine, cell division is synchronized in spare five-to-eight-day-old human blastocysts generated by IVF. A simple acetic acid disaggregation step produces discrete metaphases for G-band analysis. Subsequent FISH analysis of both metaphase and interphase nuclei allows further exploration of an abnormality detected by G-banding, including the investigation of any mosaicism. RESULTS A total of 438 blastocysts have been prepared. Where analysis was possible, 3% appeared polyploid (mainly tetraploid), 29% were diploid : tetraploid mosaics and 68% were uniformly diploid. Abnormalities observed include triploidy, trisomy 16, trisomy 2, trisomy for unidentifiable D-group chromosome, mosaic trisomy 3, and mosaic trisomy 3 and trisomy 7. CONCLUSION Comparison of results with existing data from both first trimester pregnancies and cleavage stage embryos suggests significant loss of haploid and monosomic embryos, as well as loss of some trisomies, prior to the blastocyst stage. It appears that the general range and incidence of most main groups of constitutional abnormalities observed in the first trimester (including mosaic forms) are in place by the blastocyst stage.
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Affiliation(s)
- Hazel J Clouston
- Department of Cytogenetics, Institute of Human Genetics, International Centre for Life, Newcastle upon Tyne, UK
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Abstract
OBJECTIVE To determine the incidence and type of mixoploidy in human blastocysts produced in vitro. DESIGN A laboratory study of spare blastocysts from an IVF program. SETTING University hospital laboratory. PATIENT(S) Thirty-nine couples undergoing IVF or intracytoplasmic sperm injection. INTERVENTION(S) A total of 103 blastocysts were classified as good- or poor-quality blastocysts based on morphology. A total of 6,927 interphase nuclei, 5,015 from 59 good-quality and 1,912 from 44 poor-quality blastocysts, were assessed for ploidy by fluorescence in situ hybridization with chromosome-specific DNA probes. MAIN OUTCOME MEASURE(S) The percentage and the type of polyploid cells present in each blastocyst. RESULT(S) Mixoploidy (mixture of diploid and polyploid cells) was found in 86% of good-quality and 82% of poor-quality blastocysts analyzed. The type of polyploidy ranged from 3N to 14N, with tetraploidy being the most common between both groups. The proportion of polyploid cells per mixoploid blastocyst ranged from 1% to 88%. The percentage of polyploid nuclei within most good-quality mixoploid blastocysts was small (10%) and significantly lower than in poor-quality blastocysts (19%). CONCLUSION(S) Most human blastocysts produced in vitro contain polyploid, predominantly tetraploid cells. The proportion of polyploid cells in the majority of good-quality blastocysts is low. The small numbers of blastocysts with a high percentage of polyploid cells may have implications for blastocyst transfer.
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Affiliation(s)
- Magdalena Bielanska
- Department of Obstetrics and Gynecology, Canada Royal Victoria Hospital, Montreal, Quebec, Canada
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Emiliani S, Gonzalez-Merino E, Van Den Bergh M, Delneste D, Englert Y, Abramowicz M. Correlation between fluorescence in-situ hybridization analyses and in-vitro development to blastocyst stage of embryos from Robertsonian translocation (13;14) carriers. Hum Reprod 2002; 17:2957-62. [PMID: 12407056 DOI: 10.1093/humrep/17.11.2957] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Little is known about the extent and timing of selection against the embryos that are carriers of unbalanced translocations. METHODS Fluorescence in-situ hybridization (FISH) with probes for chromosomes 13, 14 and 18 was performed, mostly on day 3, on 69 human embryos which were then allowed to develop further in culture to day 5, from five carriers of Robertsonian translocation (RT) t(13;14). RESULTS Twelve normal/balanced blastocysts were replaced in seven consecutive cycles (day 5). Three cycles resulted in clinical pregnancies. The proportion of blastocysts displaying a normal/balanced karyotype was 56%, while only the 20% of blocked embryos were normal/balanced (chi(2): P < 0.05). All the embryos analysed on day 5, except one, displayed mosaicism. The percentages of diploid cells for chromosomes 13 and 14 were significantly lower than for chromosome 18 (chromosome 13: 49.0 +/- 28.0; chromosome 14: 53.0 +/- 31.8; chromosome 18: 75.7 +/- 20.4; Mann-Whitney test: P < 0.01). The embryos displaying vertical line 62% of diploid cells for at least two of the three chromosomes analysed, more frequently reached the blastocyst stage (blocked embryos: blastocysts chromosome 13: 43.1 +/- 30.3, 64.9 +/- 29.0; chromosome 18: 64.9 +/- 29.0, 83.0 +/- 12.9; Mann-Whitney test: P < 0.01). CONCLUSIONS Normal/balanced embryos developed better but the proportion of abnormal blastocysts was still high. Preimplantation genetic diagnosis is recommended to select normal/balanced embryos from RT t(13;14) carriers.
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Affiliation(s)
- Serena Emiliani
- Fertility Clinic Erasmus Hospital, French Speaking Free University of Brussels, Route de Lennik, 808, 1070 Brussels, Belgium.
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Boiso I, Veiga A, Edwards RG. Fundamentals of human embryonic growth in vitro and the selection of high-quality embryos for transfer. Reprod Biomed Online 2002; 5:328-50. [PMID: 12470535 DOI: 10.1016/s1472-6483(10)61841-x] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Knowledge of the nature of embryo growth, and the handling and scoring of quality in human embryos are significant aspects for embryologists in IVF clinics. This review describes the formation, growth and maturation of human oocytes, many aspects of fertilization in vitro, embryonic transcription during preimplantation stages, and the formation of polarities, timing controls, role of mitochondria and functions of endocrine and paracrine systems. Modern concepts are fully discussed, together with their significance in the practice of IVF. This knowledge is essential for the correct clinical care of human embryos growing in vitro, especially in view of their uncharacteristic tendency to vary widely in implantation potential. Underlying causes of such variation have not been identified. Stringent tests must be enforced to ensure human embryos develop under optimal conditions, and are scored for quality using the most advanced techniques. Optimal methods of culture are described, including methods such as co-culture introduced to improve embryo quality but less important today. Detailed attention is given to quality as assessed from embryonic characteristics determined by timers, polarities, disturbed embryo growth and anomalous cell cycles. Methods for classification are described. Approaches to single embryo transfers are described, including the use of sequential media to produce high-quality blastocysts. These approaches, and others involved in surgical methods to remove fragments, transfer ooplasm or utilize newer approaches such as preimplantation diagnosis of chromosomal complements in embryos are covered. New outlooks in this field are summarized.
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Affiliation(s)
- Irene Boiso
- Reproductive Medicine Service, Department of Obstetrics and Gynaecology, Institut Universitari Dexeus, Paseo Bonanova 89-91, Barcelona, 08017, Spain
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Sandalinas M, Sadowy S, Alikani M, Calderon G, Cohen J, Munné S. Developmental ability of chromosomally abnormal human embryos to develop to the blastocyst stage. Hum Reprod 2001; 16:1954-8. [PMID: 11527904 DOI: 10.1093/humrep/16.9.1954] [Citation(s) in RCA: 274] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND A correlation between morphology, developmental competence and chromosome abnormalities is established. However, since absolute correlations are rare, embryo selection remains one of the most arduous tasks in assisted reproduction. This study was undertaken in order to determine which chromosomal abnormalities are compatible with development to the blastocyst stage. METHODS Embryos diagnosed by preimplantation genetic diagnosis (PGD) as chromosomally abnormal or unsuitable for transfer were cultured to day 5 or 6. Morphology and development were observed daily. After extended culture, embryos were fixed and analysed by two rounds of FISH with the same probes used for PGD. RESULTS Some types of numerical chromosome abnormalities do not preclude full differentiation in vitro. For instance, extensive mosaicism was detected in blastocysts and trisomic embryos reached the blastocyst stage with a frequency of 37%. Interestingly, only those monosomies compatible with first trimester development (monosomy X and 21) were detected at blastocyst stage. CONCLUSION Even though there is a strong selection against chromosomally abnormal embryos, extended culture to day 5 or 6 cannot be used as a reliable tool to select against clinically relevant chromosome abnormalities such as trisomies.
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Affiliation(s)
- M Sandalinas
- Gamete and Embryo Research Laboratory, The Institute for Reproductive Medicine and Science of Saint Barnabas Medical Center, West Orange, NJ 07052, USA.
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De Vos A, Van Steirteghem A. Aspects of biopsy procedures prior to preimplantation genetic diagnosis. Prenat Diagn 2001; 21:767-80. [PMID: 11559914 DOI: 10.1002/pd.172] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Today, preimplantation genetic diagnosis (PGD) is offered in over 40 centres worldwide for an expanded range of genetic defects causing disease. This very early form of prenatal diagnosis involves the detection of affected embryos by fluorescent in situ hybridization (FISH) (sex determination or chromosomal defects) or by polymerase chain reaction (PCR) (monogenic diseases) prior to implantation. Genetic analysis of the embryos involves the removal of some cellular mass from the embryos (one or two blastomeres at cleavage-stage or some extra-embryonic trophectoderm cells at the blastocyst stage) by means of an embryo biopsy procedure. Genetic analysis can also be performed preconceptionally by removal of the first polar body. However, additional information is then often gained by removal of the second polar body and/or a blastomere from the embryo. Removal of polar bodies or cellular material from embryos requires an opening in the zona pellucida, which can be created in a mechanical way (partial zona dissection) or chemical way (acidic Tyrode's solution). However, the more recent introduction of laser technology has facilitated this step enormously. Different biopsy procedures at different preimplantation stages are reviewed here, including their pros and cons and their clinical applications. The following aspects will also be discussed: safety of zona drilling by laser, use of Ca2+/Mg2+-free medium for decompaction, and removal of one or two cells from cleavage-stage embryos.
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Affiliation(s)
- A De Vos
- Centre for Reproductive Medicine, University Hospital, Dutch-speaking Brussels Free University (Vrije Universiteit Brussel), Brussels, Belgium.
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Emiliani S, Gonzalez Merino E, Van den Bergh M, Abramowicz M, Vassart G, Englert Y, Delneste D. Re-analysis by fluorescencein situ hybridisation of spare embryos cultured until Day 5 after preimplantation genetic diagnosis for a 47, XYY infertile patient demonstrates a high incidence of diploid mosaic embryos: a case report. Prenat Diagn 2001. [DOI: 10.1002/1097-0223(200012)20:13<1063::aid-pd982>3.0.co;2-f] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Petit C, Martel-Petit V, Fleurentin A, Monnier-Barbarino P, Jonveaux P, Gerard H. Use of PRINS for preconception screening of polar bodies for common aneuploidies. Prenat Diagn 2001. [DOI: 10.1002/1097-0223(200012)20:13<1067::aid-pd981>3.0.co;2-e] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Abstract
Preimplantation genetic diagnosis (PGD) includes a variety of techniques that have been developed to detect the transmission to the offspring of genetic diseases or of chromosome abnormalities by couples at risk before a pregnancy is established, to avoid these couples the risk of recurrent abortions and/or of repeated terminations of pregnancy. Candidate couples are carriers of gene mutations or of structural chromosome rearrangements, or with recurrent spontaneous abortions of unknown origin. Diagnostic procedures include different modalities of gene amplification using the polymerase chain reaction (PCR) or of fluorescent in situ hybridization (FISH). Embryo biopsies are carried out at the 6-8 cell stage. Healthy embryos are transferred on day 4 or at the blastocyst stage. By now, several hundred healthy children have been born using PGD, and only one diagnostic error has been reported.
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Affiliation(s)
- J Egozcue
- Unitat de Biologia Cel.lular, Universitat Autònoma de Barcelona, Edifici CS, 08193, Bellaterra, Spain.
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