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Wang Y, Zhao Z, Fu X, Li S, Zhang Q, Kong X. Detection of a Cryptic 25 bp Deletion and a 269 Kb Microduplication by Nanopore Sequencing in a Seemingly Balanced Translocation Involving the LMLN and LOC105378102 Genes. Front Genet 2022; 13:883398. [PMID: 36110201 PMCID: PMC9469083 DOI: 10.3389/fgene.2022.883398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 06/07/2022] [Indexed: 12/03/2022] Open
Abstract
Preimplantation genetic testing plays a critical role in enabling a balanced translocation carrier to obtain the normal embryo. Identifying the precise breakpoints for the carriers with phenotypic abnormity, allows us to reveal disrupted genes. In this study, a seemingly balanced translocation 46, XX, t (3; 6) (q29; q26) was first detected using conventional karyotype analysis. To locate the precise breakpoints, whole genomes of DNA were sequenced based on the nanopore GridION platform, and bioinformatic analyses were further confirmed by polymerase-chain-reaction (PCR) and copy number variation (CNV). Nanopore sequencing results were consistent with the karyotype analysis. Meanwhile, two breakpoints were successfully validated using polymerase-chain-reaction and Sanger Sequencing. LOC105378102 and LMLN genes were disrupted at the breakpoint junctions. Notably, observations found that seemingly balanced translocation was unbalanced due to a cryptic 269 kilobases (Kb) microduplication and a 25 bp deletion at the breakpoints of chromosome (chr) 6 and chr 3, respectively. Furthermore, 269 Kb microduplication was also confirmed by copy number variation analyses. In summary, nanopore sequencing was a rapid and direct method for identifying the precise breakpoints of a balanced translocation despite low coverage (3.8×). In addition, cryptic deletion and duplication were able to be detected at the single-nucleotide level.
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Liu D, Chen C, Zhang X, Dong M, He T, Dong Y, Lu J, Yu L, Yang C, Liu F. Successful birth after preimplantation genetic testing for a couple with two different reciprocal translocations and review of the literature. Reprod Biol Endocrinol 2021; 19:58. [PMID: 33879178 PMCID: PMC8056626 DOI: 10.1186/s12958-021-00731-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 03/10/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Preimplantation genetic testing for chromosomal structural rearrangements (PGT-SR) is widely applied in couples with single reciprocal translocation to increase the chance for a healthy live birth. However, limited knowledge is known on the data of PGT-SR when both parents have a reciprocal translocation. Here, we for the first time present a rare instance of PGT-SR for a non-consanguineous couple in which both parents carried an independent balanced reciprocal translocation and show how relevant genetic counseling data can be generated. METHODS The precise translocation breakpoints were identified by whole genome low-coverage sequencing (WGLCS) and Sanger sequencing. Next-generation sequencing (NGS) combining with breakpoint-specific polymerase chain reaction (PCR) was used to define 24-chromosome and the carrier status of the euploid embryos. RESULTS Surprisingly, 2 out of 3 day-5 blastocysts were found to be balanced for maternal reciprocal translocation while being normal for paternal translocation and thus transferable. The transferable embryo rate was significantly higher than that which would be expected theoretically. Transfer of one balanced embryo resulted in the birth of a healthy boy. CONCLUSION(S) Our data of PGT-SR together with a systematic review of the literature should help in providing couples carrying two different reciprocal translocations undergoing PGT-SR with more appropriate genetic counseling.
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Affiliation(s)
- Dun Liu
- Reproductive Medical Center, Guangdong Women and Children Hospital, Guangzhou, Guangdong, China
| | - Chuangqi Chen
- Reproductive Medical Center, Guangdong Women and Children Hospital, Guangzhou, Guangdong, China
| | - Xiqian Zhang
- Reproductive Medical Center, Guangdong Women and Children Hospital, Guangzhou, Guangdong, China
| | - Mei Dong
- Reproductive Medical Center, Guangdong Women and Children Hospital, Guangzhou, Guangdong, China
| | - Tianwen He
- Medical Genetic Centre, Guangdong Women and Children Hospital, Guangzhou, Guangdong, China
| | - Yunqiao Dong
- Reproductive Medical Center, Guangdong Women and Children Hospital, Guangzhou, Guangdong, China
| | - Jian Lu
- Medical Genetic Centre, Guangdong Women and Children Hospital, Guangzhou, Guangdong, China
| | - Lihua Yu
- Medical Genetic Centre, Guangdong Women and Children Hospital, Guangzhou, Guangdong, China
| | - Chuanchun Yang
- CheerLand Precision Biomed Co., Ltd., Shenzhen, Guangdong, China
| | - Fenghua Liu
- Reproductive Medical Center, Guangdong Women and Children Hospital, Guangzhou, Guangdong, China.
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Zhang S, Lei C, Wu J, Zhou J, Sun H, Fu J, Sun Y, Sun X, Lu D, Zhang Y. The establishment and application of preimplantation genetic haplotyping in embryo diagnosis for reciprocal and Robertsonian translocation carriers. BMC Med Genomics 2017; 10:60. [PMID: 29041973 PMCID: PMC5646120 DOI: 10.1186/s12920-017-0294-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2017] [Accepted: 10/02/2017] [Indexed: 01/11/2023] Open
Abstract
Background Preimplantation genetic diagnosis (PGD) is now widely used to select embryos free of chromosomal copy number variations (CNV) from chromosome balanced translocation carriers. However, it remains a difficulty to distinguish in embryos between balanced and structurally normal chromosomes efficiently. Methods For this purpose, genome wide preimplantation genetic haplotyping (PGH) analysis was utilized based on single nucleotide polymorphism (SNP) microarray. SNPs that are heterozygous in the carrier and, homozygous in the carrier’s partner and carrier’s family member are defined as informative SNPs. The haplotypes including the breakpoint regions, the whole chromosomes involved in the translocation and the corresponding homologous chromosomes are established with these informative SNPs in the couple, reference and embryos. In order to perform this analysis, a reference either a translocation carrier’s family member or one unbalanced embryo is required. The positions of translocation breakpoints are identified by molecular karyotypes of unbalanced embryos. The recombination of breakpoint regions in embryos could be identified. Results Eleven translocation families were enrolled. 68 blastocysts were analyzed, in which 42 were unbalanced or aneuploid and the other 26 were balanced or normal chromosomes. Thirteen embryos were transferred back to patients. Prenatal cytogenetic analysis of amniotic fluid cells was performed. The results predicted by PGH and karyotypes were totally consistent. Conclusions With the successful clinical application, we demonstrate that PGH was a simple, efficient, and popularized method to distinguish between balanced and structurally normal chromosome embryos. Electronic supplementary material The online version of this article (10.1186/s12920-017-0294-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Shuo Zhang
- Shanghai Ji Ai Genetics & IVF Institute, Obstetrics and Gynecology Hospital, Fudan University, 588 Fangxie Rd, Shanghai, 200011, China.,Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University, 2005 Songhu Rd, Shanghai, 200438, China
| | - Caixia Lei
- Shanghai Ji Ai Genetics & IVF Institute, Obstetrics and Gynecology Hospital, Fudan University, 588 Fangxie Rd, Shanghai, 200011, China.,Obstetrics and Gynecology Hospital, Fudan University, 588 Fangxie Rd, Shanghai, 200011, China
| | - Junping Wu
- Shanghai Ji Ai Genetics & IVF Institute, Obstetrics and Gynecology Hospital, Fudan University, 588 Fangxie Rd, Shanghai, 200011, China.,Obstetrics and Gynecology Hospital, Fudan University, 588 Fangxie Rd, Shanghai, 200011, China
| | - Jing Zhou
- Shanghai Ji Ai Genetics & IVF Institute, Obstetrics and Gynecology Hospital, Fudan University, 588 Fangxie Rd, Shanghai, 200011, China
| | - Haiyan Sun
- Shanghai Ji Ai Genetics & IVF Institute, Obstetrics and Gynecology Hospital, Fudan University, 588 Fangxie Rd, Shanghai, 200011, China
| | - Jing Fu
- Shanghai Ji Ai Genetics & IVF Institute, Obstetrics and Gynecology Hospital, Fudan University, 588 Fangxie Rd, Shanghai, 200011, China.,Obstetrics and Gynecology Hospital, Fudan University, 588 Fangxie Rd, Shanghai, 200011, China
| | - Yijuan Sun
- Shanghai Ji Ai Genetics & IVF Institute, Obstetrics and Gynecology Hospital, Fudan University, 588 Fangxie Rd, Shanghai, 200011, China
| | - Xiaoxi Sun
- Shanghai Ji Ai Genetics & IVF Institute, Obstetrics and Gynecology Hospital, Fudan University, 588 Fangxie Rd, Shanghai, 200011, China. .,Obstetrics and Gynecology Hospital, Fudan University, 588 Fangxie Rd, Shanghai, 200011, China.
| | - Daru Lu
- Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University, 2005 Songhu Rd, Shanghai, 200438, China.
| | - Yueping Zhang
- Shanghai Ji Ai Genetics & IVF Institute, Obstetrics and Gynecology Hospital, Fudan University, 588 Fangxie Rd, Shanghai, 200011, China. .,Obstetrics and Gynecology Hospital, Fudan University, 588 Fangxie Rd, Shanghai, 200011, China.
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Inheritance of a Chromosome 3 and 21 Translocation in the Fetuses, with One also Having Trisomy 21, in Three Pregnancies in One Family. Balkan J Med Genet 2014; 16:91-6. [PMID: 24778571 PMCID: PMC4001423 DOI: 10.2478/bjmg-2013-0039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The majority of chromosome rearrangements are balanced reciprocal and Robertsonian translocations. It is now known that such abnormalities cause no phenotypic effect on the carrier but lead to increased risk of producing unbalanced gametes. Here, we report the inheritance of a translocation between chromosomes 3 and 21 in a family with one of two fetuses with Down Syndrome carrying the same translocation and the other also carrying the same translocation without the additional chromosome 21. Chromosomal analysis from fetal amniotic fluid and peripheral blood lymphocytes from the family were performed at the Çukurova University Hospital at Adana, Turkey. We assessed a family in which the translocation between chromosomes 3 and 21 segregates: one of the three progenies carried the 47,XX,+21,t(3;21)(q21;q22) karyotype and presented with Down Syndrome; another of the three progenies carried the 46,XX,t(3;21) (q21;q22) karyotype and the third had the 46,XY karyotype. Their mother is phenotypically normal. Apparently this rearrangement occurred due to an unbalanced chromosome segregation of the mother [t(3;21)(q21;q22)mat]. This family will enable us to explain the behavior of segregation patterns and the mechanism for each type of translocation from carrier to carrier and their effects on reproduction and numerical aberrations. These findings can be used in clinical genetics and may be used as an effective tool for reproductive guidance and genetic counseling.
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Two different microarray technologies for preimplantation genetic diagnosis and screening, due to reciprocal translocation imbalances, demonstrate equivalent euploidy and clinical pregnancy rates. J Assist Reprod Genet 2014; 31:843-50. [PMID: 24771116 DOI: 10.1007/s10815-014-0230-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2013] [Accepted: 04/02/2014] [Indexed: 12/25/2022] Open
Abstract
PURPOSE To compare single nucleotide polymorphism (SNP) and comparative genomic hybridization (aCGH) microarray platforms to evaluate embryos for parental translocation imbalances and aneuploidy. METHODS A retrospective review of preimplantation genetic diagnosis and screening (PGD/PGS) results of 498 embryos from 63 couples undergoing 75 in vitro fertilization cycles due to parental carriers of a reciprocal translocation. RESULTS There was no significant difference between SNP and aCGH microarrays when comparing the prevalence of embryos that were euploid with no translocation imbalance, euploidy with a parental translocation imbalance or aneuploid with or without the parental chromosome imbalance. The clinical pregnancy rates were also equivalent for SNP (60 %) versus aCGH (65 %) microarrays. Of 498 diagnosed embryos, 45 % (226/498) were chromosomally normal without translocation errors or aneuploidy, 22 % (112/498) were euploid but had a parentally derived unbalanced chromosomal segregant, 8 % (42/498) harbored both a translocation imbalance and aneuploidy and 24 % (118/498) of embryos were genetically balanced for the parental reciprocal translocation but were aneuploid for other chromosomes. The overall clinical pregnancy rate per IVF cycle following SNP or aCGH microarray analysis was 61 % and was higher if the biopsy was done on blastocysts (65 %) versus cleavage stage embryos (59 %), although not statistically significant. CONCLUSIONS SNP or aCGH microarray technologies demonstrate equivalent clinical findings that maximize the pregnancy potential in patients with known parental reciprocal chromosomal translocations.
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