Preimplantation genetic testing (PGT) is presently the only option available for detecting genetic conditions in embryos created through in vitro fertilization (IVF) prior to implantation. Thus PGT eliminates the dilemma of pregnancy termination following unfavorable prenatal diagnosis test results. Complex chromosome rearrangements (CCRs), although very rarely reported in humans, represent a significant clinical problem for their carriers. CCRs include at least three breakpoints affecting two or more chromosomes. In three-breakpoint translocations, theoretically sixty-four different chromosomal sets are produced. Only two of them will be balanced and will lead to the birth of a phenotypically normal child. Therefore, CCR carriers are at increased risk of chromosomally unbalanced conceptions, resulting in spontaneous abortions or birth of offspring with intellectual disability and/or congenital anomalies. The reproductive options before such families are: natural conception followed by prenatal diagnosis; donor gametes; adoption or PGT. In this paper we discuss the current state of the PGT field and report on two PGT-cases for CCR in families with infertility and recurrent pregnancy losses. The families underwent IVF-PGT on day 3 and day 5 embryos and whole genome microarray analysis.
ARTICLE HISTORY
Preimplantation genetic test (PGT) is cutting-edge technology for early detection of genetic abnormalities in embryos prior to their implantation in the uterus. PGT prevents the transfer of affected embryos during in vitro fertilization (IVF) procedures and termination of pregnancy. In our study we report the results from 185 couples with history of infertility and pregnancy loss that had undergone IVF procedures with PGT. Trophectoderm biopsy was carried out on 497 blastocyst stage embryos originating from 231 oocyte retrieval cycles. Array-based comparative genomic hybridization (aCGH) and next-generation sequencing (NGS) were subsequently performed. One hundred and ninety-six embryos had balanced profile (40.16%) and 292 embryos showed unbalanced profile (59.84%). Embryo transfer was performed in 109 cases (58.92%) and biochemical pregnancy was reported in 33.03%. Live birth rate was 29.36% and pregnancy loss occurred in 3.67% of cases. Our results show that PGT reduces the number of meaningless transfers, eliminates the trauma of termination of desired pregnancy and possible medical complications. In couples with reproductive failure PGT decreases the risk for pregnancy loss, increases the chance of conceiving with a chromosomally balanced embryo and live birth of a healthy offspring per transfer.
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