Application of FISH method for preimplantation genetic diagnostics of reciprocal and Robertsonian translocations

Abstract

Introduction. Carriers of reciprocal (RCP) and Robertsonian (RT) translocations are known to be at risk for reproductive difficulties. Preimplantation genetic diagnosis (PGD) is one of the options these carriers have to try to fulfill their desire to have a child. The FISH technique is one of the best method to detect RCPs, and, together with the Next Generation Sequencing, to diagnose RTs. The aim of the present study was to assess the usefulness of the FISH method for rapid diagnosis of translocations in our center to improve the reproductive counseling. Material and methods. From 2008 to 2012 one hundred and twenty seven fresh cycles of the in vitro fertilization (IVF; without freezing embryos) were performed in 42 couples with an RCP and 35 couples with an RT translocations. The patients were diagnosed before IVF as translocation carriers and therefore they opted for PGD. The classical FISH protocol has been applied with specific oligonucleotide probes. Results.In total 521 blastomeres were tested in order to determine the presence or absence of genetic anomalies resulting from one of the parents being a translocation carrier. Despite the large number of abnormal embryos (407 embryos -78.1% of all examined embryos), 19.4% of blastomeres appeared to come from a normal or balanced embryos that may have been transferred to the uterus. In 63 of the 127 cycles embryo transfer (ET) was feasible and 24 women had a successful singleton or twin pregnancy. Thus, a live delivery rate of 18.9% per started cycles and 38.1% per cycle with ET was obtained. Conclusion. FISH should be regarded as an optimal preimplantation genetic diagnosis method for specific RCP and RT translocation carriers to increase the chance of successful IVF procedure.

Next Generation Sequencing (NGS) in chromosome translocation 46, XX, t (9; X) (q22; q28) - a case report

“…Five hundred and forty-eight embryos were biopsied and 101 euploid embryos were found, yielding a euploidy rate of 19.4%. A study carried out by our group examined nine patients with translocations identified with CGH-array and/or NGS tests and found fertilization and euploidy rates of 84% and 38%, respectively, similarly to Liss et al . (2015) .…”

“… Liss et al . (2015) studied 42 couples with reciprocal translocation and 35 with Robertsonian translocation through the FISH technique.…”

Nanopore sequencing for detecting reciprocal translocation carrier status in preimplantation genetic testing

“…Importantly, carriers can avoid physical and psychological trauma due to recurrent miscarriage or termination of the affected pregnancy upon selective transfer of normal or balanced diploid embryos. Several methods have been applied to PGT-SR, including fluorescence in situ hybridization (FISH) [ 10 , 11 ], single-nucleotide polymorphism (SNP) arrays [ 12 , 13 ], array comparative genomic hybridization (aCGH) [ 8 , 14 ], and next-generation sequencing (NGS) [ 15 – 17 ]. The initial FISH method is limited to the detection of several specific chromosomes, and the results are sometimes uncertain due to ambiguous optical signals of the fluorescent probes and complex sample preparation procedures [ 17 – 20 ].…”

Time-lapse imaging reveals delayed development of embryos carrying unbalanced chromosomal translocations

“…Both male and female carriers of balanced translocations typically do not exhibit any adverse phenotypic effect themselves, but more than 60% of their gametes are predicted to be unbalanced, leading to abnormal embryos. These individuals are therefore at risk for infertility, repeated implantation failures, pregnancy loss, and birth defects [1][2][3][4]. Indeed, while balanced translocations are found in only 0.2% of the neonatal population, the incidence is higher among infertile couples (0.6%) and in women with recurrent miscarriages (9.2%).…”