scholarly journals De novo balanced reciprocal translocation mosaic t(1;3)(q42;q25) detected by prenatal genetic diagnosis: a fetus conceived using preimplantation genetic testing due to a t(12;14)(q22;q13) balanced paternal reciprocal translocation

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Shaoqin Zhang ◽  
Jianjiang Zhu ◽  
Hong Qi ◽  
Limei Xu ◽  
Lirong Cai ◽  
...  

Abstract Introduction De novo balanced reciprocal translocations mosaicism in fetus conceived using preimplantation genetic testing from a different balanced translocation carrier parent has been rarely reported. Methods Chromosomal microarray analysis, karyotype analysis and fluorescent in situ hybridization were performed to verify the type and heredity of the rearrangement. STR analysis was conducted to identify potential contamination and verify kinship. In addition, a local BLAST engine was performed to locate potentially homologous segments which might contribute to the translocation in breakpoints of chromosome. Results A rare de novo balanced reciprocal translocations mosaicism mos 46,XY,t(1;3)(q42;q25)[40]/46,XY[39] was diagnosed in a fetus conceived using preimplantation genetic testing due to a 46,XY,t(12;14)(q22;q13) balanced translocation carrier father through multiplatform genetic techniques. Two of the largest continuous high homology segments were identified in chromosomal band 1q42.12 and 3q25.2. At the 21-months follow up, infant has achieved all psychomotor development milestones as well as growth within the normal reference range. Conclusion We present a prenatal diagnosis of a rare de novo balanced reciprocal translocations mosaicism in a fetus who conceived by preimplantation genetic testing. The most reasonable driving mechanism was that a de novo mitotic error caused by nonallelic homologous recombination between 1q42.12 and 3q25.2 in a zygote within the first or early cell divisions, which results in a mosaic embryo with the variant present in a half proportion of cells.

2021 ◽  
Author(s):  
Shaoqin Zhang ◽  
jianjiang zhu ◽  
Hong Qi ◽  
Limei Xu ◽  
Lirong Cai ◽  
...  

Abstract IntroductionPreimplantation genetic testing (PGT) had widely been applied in reciprocal translocation carriers to improve the clinical outcome of assisted reproduction. De novo mosaicism balanced reciprocal translocations in fetus conceived using PGT from a balanced translocation carrier parent has been rarely reported, and the driving mechanism is not clearly. MethodsChromosomal microarray analysis (CMA) , karyotype analysis and fluorescent in situ hybridization (FISH) were performed to verify the type and heredity of the rearrangement. STR analysis was used to identify potential contamination as well as kinship verification and identification. ResultsA rare de novo mosaicism balanced reciprocal translocation t(1,3)(q42;q25) in fetus conceived using PGT-SR from a t(12;14)(q22;q13) balanced translocation carrier father was been diagnosed by multiplatform genetic techniques. At 31 weeks and 2 days of gestation, premature delivery was caused by uncontrollable uterine contractions. At the 21-months follow up, infant has achieved all psychomotor development milestones as well as growth within the normal reference range. ConclusionPGT cases still need close observation in prenatal diagnosis and long-term follow-up.


2020 ◽  
Author(s):  
Dun Liu ◽  
Chuangqi Chen ◽  
Xiqian Zhang ◽  
Mei Dong ◽  
Tianwen He ◽  
...  

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, 66.7% 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.


2021 ◽  
Vol 12 ◽  
Author(s):  
Yinghui Ye ◽  
Jieliang Ma ◽  
Long Cui ◽  
Sijia Lu ◽  
Fan Jin

Nowadays, most of the preimplantation genetic testing (PGT) is performed with a strategy of comprehensive chromosome screening and trophectoderm biopsy. Nevertheless, patients with ovarian insufficiency may not have competent blastocysts. In the present study, we aimed to establish the value of multiple annealing and looping-based amplification cycle (MALBAC)-based next-generation sequencing (NGS) for PGT in day-3 embryos. A total of 94.3% (1168/1239) of embryos yielded informative results, and the overall embryo euploid rate was 21.9% (256/1168). Overall, 225 embryos were transferred in 169 cycles with a clinical pregnancy rate of 49.1% (83/169). The live birth and implantation rates were 47.3% (80/169) and 44.4% (100/225), respectively. Double embryos transfer showed higher clinical pregnancy and live birth rates compared with single embryo transfer, but the implantation rates were similar (44.2% vs. 44.6%, P > 0.05). The euploid rate for reciprocal translocations (16.1%) was significantly lower than that for Robertsonian translocations (28.0%, P < 0.01) and inversions (28.0%, P < 0.01). However, higher percentages of embryos with de novo abnormalities were observed with Robertsonian translocations (23.3%, P < 0.01) and inversions (30.5%, P < 0.01) than with reciprocal translocations (11.6%). We demonstrated that NGS for PGT on day-3 embryos is an effective clinical application, particularly for patients with a diminished ovarian reserve and limited embryos.


2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Dun Liu ◽  
Chuangqi Chen ◽  
Xiqian Zhang ◽  
Mei Dong ◽  
Tianwen He ◽  
...  

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.


2021 ◽  
pp. 1-9
Author(s):  
Hongfang Liu ◽  
Bin Mao ◽  
Xiaojuan Xu ◽  
Lin Liu ◽  
Xiaoling Ma ◽  
...  

The purpose of this study was to evaluate the effectiveness of next-generation sequencing (NGS)-based preimplantation genetic testing (PGT) for balanced translocation carriers to identify normal/balanced blastocysts and to measure pregnancy outcomes following euploid embryo transfer. We enrolled 75 couples with a balanced translocation who underwent 83 PGT cycles (58 cycles for carriers with reciprocal translocations and 25 cycles for carriers with Robertsonian translocations) and 388 blastocysts were diagnosed. Moreover, we transferred single euploid blastocysts through frozen embryo transfer and calculated the biochemical pregnancy, clinical pregnancy, miscarriage, and ongoing pregnancy rates per embryo transfer cycle. Despite a mean maternal age of 29.8 years and mean of 4.34 embryos biopsied, there was a 32.8% chance of recording no chromosomally normal/balanced embryos for reciprocal translocation carriers. The proportion of normal/balanced embryos was significantly higher (44.1 vs. 27.8%) in Robertsonian translocation carriers than in reciprocal translocation carriers. Female carriers had a significantly lower (23.3 vs. 42.4%, 34.7 vs. 54.7%, respectively) percentage of normal/balanced embryos than male carriers, regardless of the translocation. After transfering single blastocysts, we obtained a 64.4% clinical pregnancy rate per transfer, and the clinical miscarriage rate was 5.7%. Amniocentesis results showed that all karyotypes of the fetuses were consistent with PGT results. The clinical outcomes are probably not influenced by the type of translocation, maternal age, and blastocyst morphology following the transfer of euploid blastocysts. Therefore, we conclude that NGS-based PGT is an efficient method for analyzing balanced translocation carriers, and aneuploidy screening had good clinical outcomes.


2020 ◽  
Author(s):  
Qing Li ◽  
Yan Mao ◽  
Shaoying Li ◽  
Hongzi Du ◽  
Wenzhi He ◽  
...  

Abstract Background: In order to mitigate the risk of allele dropout (ADO) and ensure the accuracy of preimplantation genetic testing for monogenic disease (PGT-M), it is necessary to construct parental haplotypes.. Typically, haplotype resolution is obtained by genotyping multiple polymorphic markers in both parents and a proband or a relative. Sometimes, single sperm typing, or tests on the polar bodies may also be useful. Nevertheless, this process is time-consuming. At present, there was no simple linkage analysis strategy for patients without affected relatives.Method: To solve this problem, we established a haplotyping by linked-read sequencing (HLRS) method without the requirement for additional relatives. First, the haplotype of the genetic disease carriers in the family was constructed by linked-read sequencing, and then the informative single nucleotide polymorphisms (SNPs) in upstream and downstream mutation region were selected to construct the embryo haplotype and to determine whether the embryo was carrying the mutation. Two families were selected to validate this method; one with alpha thalassemia and the other with NDP gene disorder.Results: The haplotyping by linked-read sequencing (HLRS) method was successfully applied to construct parental haplotypes without recruiting additional family members; the method was also validated for PGT-M. The mutation carriers in these families were sequenced by linked-read sequencing, and their haplotypes were successfully phased. Adjacent SNPs of the mutation gene were identified. The informative SNPs were chosen for linkage analyses to identify the carrier embryos. For the alpha thalassemia family, a normal blastocyst was transferred to the uterus and the accuracy of PGT-M was confirmed by amniocentesis at 16 weeks of gestation. Conclusions: Our results suggest that HLRS can be applied for PGT-M of monogenic disorders or de novo mutations where the mutations haplotype cannot be determined due to absence of affected relatives. Keywords: Preimplantation Genetic Testing for monogenic disease, Linked-read sequencing, Linkage analyses, Haplotype


Author(s):  
М.Е. Миньженкова ◽  
Ж.Г. Маркова ◽  
И.В. Анисимова ◽  
И.В. Канивец ◽  
Н.В. Шилова

Выяснение этиопатогенеза аномального фенотипа у пациентов со сбалансированными транслокациями является актуальным аспектом в современной клинической цитогенетике. Формирование аномалий развития может быть ассоциировано с наличием скрытого геномного дисбаланса как в точках разрывов, так и на хромосомах, не задействованных в перестройке. Целью данного исследования явилась этиологическая диагностика геномного дисбаланса у пациента со сбалансированной транслокацией и аномалиями развития. Для детекции геномного дисбаланса у пациента со сбалансированной транслокацией использовали хромосомный микроматричный анализ (ХМА) и FISH-исследование. У пациента со сбалансированной транслокацией при ХМА была выявлена делеция на хромосоме 8, не задействованной в транслокации. Таким образом, в статье представлен новый случай делеции 8q22.2q22.3 у пациента со сбалансированной транслокацией t(1;6) и аномалиями развития вследствие делеции. Identification of the etiopathogenesis of the abnormal phenotype in patients with balanced translocations is current trend in cytogenetic laboratories. The formation of developmental anomalies can be associated with the presence of a cryptic genomic imbalance both at breakpoints and on chromosomes not involved in rearrangements.The aim of this study is diagnostics of genomic imbalance in a patient with balanced translocation and abnormal phenotype. The case was characterized by GTG-banding, chromosomal microarray analysis and FISH diagnosis. We present a new case of deletion 8q22.2-q22.3 in child with balanced translocation t(1;6) and developmental delay/congenital defects due to deletion.


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