1
|
Whether to transfer mosaic embryos: a cytogenetic view of true mosaicism by amniocentesis. Reprod Biomed Online 2021; 43:33-43. [PMID: 33962907 DOI: 10.1016/j.rbmo.2021.03.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 02/26/2021] [Accepted: 03/03/2021] [Indexed: 11/21/2022]
Abstract
RESEARCH QUESTION Preimplantation genetic testing for aneuploidies has increasingly been employed for embryo selection, resulting in a recent surge in mosaic embryos. According to the cytogenetic results, which types of mosaic embryo survive early pregnancy, progress to the second trimester and finally result in a live birth? DESIGN This study evaluated 30,587 pregnant women undergoing amniocentesis from January 2004 to March 2020 at the cytogenic centre of Kaohsiung Chang Gung Memorial Hospital. Samples from amniocentesis were cultured using the in-situ method. The types and distribution of level III chromosomal mosaicism (two or more cells with the same abnormality in two or more colonies and both culture dishes, clinically referred to as 'true mosaicism') were retrospectively reviewed. RESULTS Among the 30,587 women, 78 cases (0.26%) of level III chromosomal mosaicism were identified. The types of chromosomal mosaicism were classified as sex chromosome mosaicism (SCM), autosomal chromosome mosaicism (ACM) and marker chromosome mosaicism (MCM), with SCM, ACM and MCM accounting for 58.97%, 32.05% and 8.97% of cases, respectively. The most common mosaic cell lines were monosomy X and trisomy 21. The most common mosaic cell line progressing to live birth was monosomy X. CONCLUSIONS Mosaic monosomy X and trisomy 21 are the most common cell lines of true mosaicism determined by amniocentesis. Monosomy X mosaicism is the most common cell line in live births. For women considering the transfer of these types of mosaic embryo in a circumstance where euploid embryos are unavailable, clinicians should provide careful prenatal counselling, detailed ultrasonography and amniocentesis.
Collapse
|
2
|
Friedenthal J, Maxwell SM, Munné S, Kramer Y, McCulloh DH, McCaffrey C, Grifo JA. Next generation sequencing for preimplantation genetic screening improves pregnancy outcomes compared with array comparative genomic hybridization in single thawed euploid embryo transfer cycles. Fertil Steril 2018; 109:627-632. [DOI: 10.1016/j.fertnstert.2017.12.017] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2017] [Revised: 11/30/2017] [Accepted: 12/15/2017] [Indexed: 10/17/2022]
|
3
|
Natural selection between day 3 and day 5/6 PGD embryos in couples with reciprocal or Robertsonian translocations. J Assist Reprod Genet 2017; 34:1483-1492. [PMID: 28756497 DOI: 10.1007/s10815-017-1009-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 07/21/2017] [Indexed: 10/19/2022] Open
Abstract
PURPOSE For translocation carriers, preimplantation genetic diagnosis (PGD) provides the opportunity to distinguish between normal/balanced and unbalanced embryos prior to implantation and, as such, increases the likelihood of a successful ongoing pregnancy. The data presented here compares autosomal reciprocal and Robertsonian translocation segregation patterns in day 3 versus day 5/6 IVF-PGD embryos to determine if there is a difference in the chromosome segregation patterns observed at these developmental time points. METHODS A retrospective analysis on PGD translocation carriers at Monash IVF was performed. Segregation patterns were compared between day 3 and day 5/6 embryos to ascertain whether selection against malsegregants exists. RESULTS For reciprocal translocations, 1649 day 3 embryos (139 translocations) from 144 couples and 128 day 5/6 embryos (59 translocations) from 60 couples were analysed. Day 3 segregation analysis showed that 22.3% of embryos were normal/balanced (consistent with 2:2 alternate segregation) and 77.7% were unbalanced (malsegregation). Day 5/6 segregation analysis showed that 53.1% of embryos were normal/balanced and 46.9% were unbalanced. For Robertsonian translocations, 847 day 3 embryos (8 translocations) from 54 couples and 193 day 5/6 embryos (6 translocations) from 31 couples were analysed. Day 3 segregation analysis showed that 38.7% of embryos were normal/balanced (consistent with 2:1 alternate segregation) and 61.3% were unbalanced. Day 5/6 segregation analysis showed that 74.1% of embryos were normal/balanced and 25.9% were unbalanced. CONCLUSIONS This data demonstrates an increase in the proportion of genetically normal/balanced embryos at day 5/6 of development. This suggests a strong natural selection process between day 3 and day 5/6 in favour of normal/balanced embryos. These findings support performing PGD testing on day 5/6 of embryo development.
Collapse
|
4
|
McCoy RC. Mosaicism in Preimplantation Human Embryos: When Chromosomal Abnormalities Are the Norm. Trends Genet 2017; 33:448-463. [PMID: 28457629 DOI: 10.1016/j.tig.2017.04.001] [Citation(s) in RCA: 131] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 03/31/2017] [Accepted: 04/03/2017] [Indexed: 11/15/2022]
Abstract
Along with errors in meiosis, mitotic errors during post-zygotic cell division contribute to pervasive aneuploidy in human embryos. Relatively little is known, however, about the genesis of these errors or their fitness consequences. Rapid technological advances are helping to close this gap, revealing diverse molecular mechanisms contributing to mitotic error. These include altered cell cycle checkpoints, aberrations of the centrosome, and failed chromatid cohesion, mirroring findings from cancer biology. Recent studies are challenging the idea that mitotic error is abnormal, emphasizing that the fitness impacts of mosaicism depend on its scope and severity. In light of these findings, technical and philosophical limitations of various screening approaches are discussed, along with avenues for future research.
Collapse
Affiliation(s)
- Rajiv C McCoy
- Department of Genome Sciences, University of Washington, Seattle, WA, USA.
| |
Collapse
|
5
|
Gleicher N, Metzger J, Croft G, Kushnir VA, Albertini DF, Barad DH. A single trophectoderm biopsy at blastocyst stage is mathematically unable to determine embryo ploidy accurately enough for clinical use. Reprod Biol Endocrinol 2017; 15:33. [PMID: 28449669 PMCID: PMC5408377 DOI: 10.1186/s12958-017-0251-8] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 04/20/2017] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND It has become increasingly apparent that the trophectoderm (TE) at blastocyst stage is much more mosaic than has been appreciated. Whether preimplantation genetic screening (PGS), utilizing a single TE biopsy (TEB), can reliably determine embryo ploidy has, therefore, increasingly been questioned in parallel. METHODS We for that reason here established 2 mathematical models to assess probabilities of false-negative and false-positive results of an on average 6-cell biopsy from an approximately 300-cell TE. This study was a collaborative effort between investigators at The Center for Human Reproduction in New York City and the Center for Studies in Physics and Biology and the Brivanlou Laboratory of Stem Cell Biology and Molecular Embryology, the latter two both at Rockefeller University in New York City. RESULTS Both models revealed that even under best case scenario, assuming even distribution of mosaicism in TE (since mosaicism is usually clonal, a highly unlikely scenario), a biopsy of at least 27 TE cells would be required to reach minimal diagnostic predictability from a single TEB. CONCLUSIONS As currently performed, a single TEB is, therefore, mathematically incapable of reliably determining whether an embryo can be transferred or should be discarded. Since a single TEB, as currently performed, apparently is not representative of the complete TE, this study, thus, raises additional concern about the clinical utilization of PGS.
Collapse
Affiliation(s)
- Norbert Gleicher
- The Center for Human Reproduction, 21 East 69th Street, New York, NY, 10021, USA.
- Foundation for Reproductive Medicine, New York, NY, 10022, USA.
- Laboratory of Stem Cell Biology and Molecular Embryology, The Rockefeller University, New York, NY, 10065, USA.
- Department of Obstetrics and Gynecology, University of Vienna School of Medicine, 1090, Vienna, Austria.
| | - Jacob Metzger
- Center for Studies in Physics and Biology, The Rockefeller University, New York, NY, 10065, USA
| | - Gist Croft
- Laboratory of Stem Cell Biology and Molecular Embryology, The Rockefeller University, New York, NY, 10065, USA
| | - Vitaly A Kushnir
- The Center for Human Reproduction, 21 East 69th Street, New York, NY, 10021, USA
- Department of Obstetrics and Gynecology, Wake Forest University, Winston Salem, NC, 27109, USA
| | - David F Albertini
- The Center for Human Reproduction, 21 East 69th Street, New York, NY, 10021, USA
- Laboratory of Stem Cell Biology and Molecular Embryology, The Rockefeller University, New York, NY, 10065, USA
| | - David H Barad
- The Center for Human Reproduction, 21 East 69th Street, New York, NY, 10021, USA
- Foundation for Reproductive Medicine, New York, NY, 10022, USA
| |
Collapse
|
6
|
Vera-Rodriguez M, Rubio C. Assessing the true incidence of mosaicism in preimplantation embryos. Fertil Steril 2017; 107:1107-1112. [PMID: 28433370 DOI: 10.1016/j.fertnstert.2017.03.019] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 03/21/2017] [Indexed: 10/19/2022]
Abstract
Modern technologies applied to the field of preimplantation genetic diagnosis for aneuploidy screening (PGD-A) have improved the ability to identify the presence of mosaicism. Consequently, new questions can now be addressed regarding the potential impact of embryo mosaicism on diagnosis accuracy and the feasibility of considering mosaic embryos for transfer. The frequency of chromosomal mosaicism in products of conception (POCs) of early miscarriages has been reported to be low. Mosaic embryos with an aneuploid inner cell mass are typically lost during the first trimester owing to spontaneous miscarriages. Most of the mosaics in established pregnancies would derive from placental mosaicism or placental aneuploidy, and mosaic embryos with aneuploid inner cell mass should be lost mainly due to first-trimester spontaneous miscarriages. The well described clinical outcomes of live births from mosaic embryos suggest a wide spectrum of phenotypes, from healthy to severely impaired. Therefore, there is a need to balance the risks of discarding a possibly viable embryo with that of transferring an embryo that may ultimately have a lower implantation potential.
Collapse
Affiliation(s)
| | - Carmen Rubio
- Igenomix and Igenomix Foundation, Valencia, Spain.
| |
Collapse
|
7
|
Besser AG, Mounts EL. Counselling considerations for chromosomal mosaicism detected by preimplantation genetic screening. Reprod Biomed Online 2017; 34:369-374. [DOI: 10.1016/j.rbmo.2017.01.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 11/07/2016] [Accepted: 01/05/2017] [Indexed: 02/04/2023]
|
8
|
Sachdev NM, Maxwell SM, Besser AG, Grifo JA. Diagnosis and clinical management of embryonic mosaicism. Fertil Steril 2017; 107:6-11. [DOI: 10.1016/j.fertnstert.2016.10.006] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 09/30/2016] [Accepted: 10/03/2016] [Indexed: 11/16/2022]
|
9
|
Präimplantationsdiagnostik – methodische Aspekte. MED GENET-BERLIN 2016. [DOI: 10.1007/s11825-016-0103-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Zusammenfassung
Die Präimplantationsdiagnostik erfordert eine enge und vertrauensvolle interdisziplinäre Zusammenarbeit zwischen hoch qualifizierten Fachärzten und Naturwissenschaftlern aus Humangenetik und Reproduktionsmedizin. In einem sehr engen Zeitfenster müssen komplexe Laborabläufe standardisiert und qualitätsgesichert umgesetzt werden. In diesem Beitrag sollen orientierende Empfehlungen zur Umsetzung kurz vorgestellt werden. Zentral haben wir häufigere Problemsituationen thematisiert, welche bereits bei der Indikationsstellung wie auch bei den nachfolgenden Schritten in der genetischen Analyse, Datenauswertung und Befunderstellung mögliche Fehlerquellen darstellen. Ziel unserer verantwortlichen Arbeit an den PID-Zentren sollte eine hohe Geburtenrate bei hoher Diagnosesicherheit mit möglichst wenigen schonenden Behandlungszyklen sein.
Collapse
|
10
|
Treff NR, Franasiak JM. Detection of segmental aneuploidy and mosaicism in the human preimplantation embryo: technical considerations and limitations. Fertil Steril 2016; 107:27-31. [PMID: 27816233 DOI: 10.1016/j.fertnstert.2016.09.039] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 09/19/2016] [Accepted: 09/21/2016] [Indexed: 01/12/2023]
Abstract
Whole-chromosome aneuploidy screening has become a common practice to improve outcomes and decrease embryonic transfer order in patients undergoing treatment for infertility through in vitro fertilization. Despite implementation of this powerful technology, a significant percentage of euploid embryos fail to result in successful deliveries. As technology has evolved, detection of subchromosomal imbalances and embryonic mosaicism has become possible, and these serve as potential explanations for euploid embryo transfer failures. Cases involving a parent with a balanced translocation provide a unique opportunity to characterize the capabilities and limitations of detecting segmental imbalances with a variety chromosome screening platforms. Adaptation of these methods to de novo imbalances now represent an ongoing challenge in the field of preimplantation genetic screening as additional factors including mosaicism, clinical predictive value, and distinguishing true imbalances from technical artifacts must be more carefully considered.
Collapse
Affiliation(s)
- Nathan R Treff
- Reproductive Medicine Associates of New Jersey, Basking Ridge, New Jersey; Thomas Jefferson University, Philadelphia, Pennsylvania.
| | | |
Collapse
|
11
|
Why do euploid embryos miscarry? A case-control study comparing the rate of aneuploidy within presumed euploid embryos that resulted in miscarriage or live birth using next-generation sequencing. Fertil Steril 2016; 106:1414-1419.e5. [DOI: 10.1016/j.fertnstert.2016.08.017] [Citation(s) in RCA: 127] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 08/05/2016] [Accepted: 08/05/2016] [Indexed: 11/16/2022]
|
12
|
Gleicher N, Vidali A, Braverman J, Kushnir VA, Barad DH, Hudson C, Wu YG, Wang Q, Zhang L, Albertini DF. Accuracy of preimplantation genetic screening (PGS) is compromised by degree of mosaicism of human embryos. Reprod Biol Endocrinol 2016; 14:54. [PMID: 27595768 PMCID: PMC5011996 DOI: 10.1186/s12958-016-0193-6] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 08/30/2016] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND To preclude transfer of aneuploid embryos, current preimplantation genetic screening (PGS) usually involves one trophectoderm biopsy at blastocyst stage, assumed to represent embryo ploidy. Whether one such biopsy can correctly assess embryo ploidy has recently, however, been questioned. METHODS This descriptive study investigated accuracy of PGS in two ways. Part I: Two infertile couples donated 11 embryos, previously diagnosed as aneuploid and, therefore, destined to be discarded. They were dissected into 37 anonymized specimens, and sent to another national laboratory for repeat analyses to assess (i) inter-laboratory congruity and (ii) intra-embryo congruity of multiple embryo biopsies in a single laboratory. Part II: Reports on human IVF cycle outcomes after transfer of allegedly aneuploid embryos into 8 infertile patients. RESULTS Only 2/11 (18.2 %) embryos were identically assessed at two PGS laboratories; 4/11 (36.4 %), on repeat analysis were chromosomally normal, 2 mosaic normal/abnormal, and 5/11 (45.5 %) completely differed in reported aneuploidies. In intra-embryo analyses, 5/10 (50 %) differed between biopsy sites. Eight transfers of previously reported aneuploid embryos resulted in 5 chromosomally normal pregnancies, 4 delivered and 1 ongoing. Three patients did not conceive, though 1 among them experienced a chemical pregnancy. CONCLUSIONS Though populations of both study parts are too small to draw statistically adequately powered conclusions on specific degrees of inaccuracy of PGS, here presented results do raise concerns especially about false-positive diagnoses. While inter-laboratory variations may at least partially be explained by different diagnostic platforms utilized, they cannot explain observed intra-embryo variations, suggesting more frequent trophectoderm mosiaicsm than previously reported. Together with recentl published mouse studies of lineages-specific degrees of survival of aneuploid cells in early stage embryos, these results call into question the biological basis of PGS, based on the assumption that a single trophectoderm biopsy can reliably determine embryo ploidy.
Collapse
Affiliation(s)
- Norbert Gleicher
- The Center for Human Reproduction, 21 East 69th Street, New York, NY 10021 USA
- The Foundation for Reproductive Medicine, New York, NY USA
- The Brivanlou Laboratory for Stem Cell Biology and Molecular Embryology, Rockefeller University, New York, NY USA
| | - Andrea Vidali
- The Center for Human Reproduction, 21 East 69th Street, New York, NY 10021 USA
- Fertility Specialist in New York, New York, NY USA
| | | | - Vitaly A. Kushnir
- The Center for Human Reproduction, 21 East 69th Street, New York, NY 10021 USA
- Department of Obstetrics and Gynecology, Wake Forest University, Winston Salem, NC USA
| | - David H. Barad
- The Center for Human Reproduction, 21 East 69th Street, New York, NY 10021 USA
- The Foundation for Reproductive Medicine, New York, NY USA
- Department of Obstetrics and Gynecology, Albert Einstein College of Medicine, Bronx, NY USA
| | - Cynthia Hudson
- The Center for Human Reproduction, 21 East 69th Street, New York, NY 10021 USA
| | - Yang-Guan Wu
- The Center for Human Reproduction, 21 East 69th Street, New York, NY 10021 USA
| | - Qi Wang
- The Center for Human Reproduction, 21 East 69th Street, New York, NY 10021 USA
| | - Lin Zhang
- The Center for Human Reproduction, 21 East 69th Street, New York, NY 10021 USA
| | - David F. Albertini
- The Center for Human Reproduction, 21 East 69th Street, New York, NY 10021 USA
- Department of Molecular and Integrative Physiology, University of Kansas School of Medicine, Wichita, KS USA
| | | |
Collapse
|
13
|
Esfandiari N, Bunnell ME, Casper RF. Human embryo mosaicism: did we drop the ball on chromosomal testing? J Assist Reprod Genet 2016; 33:1439-1444. [PMID: 27577322 DOI: 10.1007/s10815-016-0797-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2016] [Accepted: 08/16/2016] [Indexed: 12/27/2022] Open
Abstract
There are newly recognized challenges presented by the occurrence of mosaicism in the context of trophectoderm (TE) biopsy for pre-implantation genetic screening (PGS) in in vitro fertilization (IVF) embryos. Chromosomal mosaicism, known to be significantly higher in IVF embryos than in later prenatal samples, may contribute to errors in diagnosis. In particular, PGS may result in discarding embryos diagnosed as aneuploid but in which the inner cell mass may be completely or mainly euploid, thus representing a false positive diagnosis. Although less likely, some embryos diagnosed as euploid could be mosaic and contain some aneuploid cells, possibly impacting their implantation potential. The ability of current diagnostic techniques to detect mosaicism is limited by the number and location of TE cells in the biopsy and by the methodology used for chromosomal assessment. The clinical consequences of mosaicism are dependent on the chromosome(s) involved, the developmental stage at which the mosaicism evolved, and whether TE biopsy accurately reflects the status of the inner cell mass that forms the fetus. Consequently, in patients with no euploid embryos identified on PGS, it may be appropriate to consider the transfer of diagnosed aneuploid embryos if the TE biopsy result is a non-viable chromosomal monosomy or triploidy that could not result in a birth. It should be acknowledged in consent forms that mosaicism has the potential to impact test results and that its detection may be below the resolution of the genetic tests being used. This concept represents a major shift in current IVF practice and ought to be considered given the data, or lack thereof, of the impact of mosaicism on IVF/PGS outcomes.
Collapse
Affiliation(s)
- Navid Esfandiari
- Division of Reproductive Endocrinology and Infertility, Department of OB-GYN, Dartmouth Hitchcock Medical Center, Geisel School of Medicine, Lebanon, NH, USA.
| | - Megan E Bunnell
- Division of Reproductive Endocrinology and Infertility, Department of OB-GYN, Dartmouth Hitchcock Medical Center, Geisel School of Medicine, Lebanon, NH, USA
| | - Robert F Casper
- Division of Reproductive Endocrinology and Infertility., Department of OB-GYN, School of Medicine, University of Toronto, Toronto, Canada
| |
Collapse
|
14
|
Mosaicism: “survival of the fittest” versus “no embryo left behind”. Fertil Steril 2016; 105:1146-1149. [DOI: 10.1016/j.fertnstert.2016.01.016] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Revised: 01/08/2016] [Accepted: 01/11/2016] [Indexed: 11/18/2022]
|