Clinical outcomes in carriers of complex chromosomal rearrangements: a retrospective analysis of comprehensive chromosome screening results in seven cases

Abstract

The chances of identifying normal/balanced blastocysts in patients with CCR are <6%; the chances of a pregnancy are <4%. Greater complexity CCRs result in fewer transplantable embryos. Moreover, CCRs of greater complexity have a lower rate of high quality blastocysts than CCRs of less complexity.

The influence of balanced complex chromosomal rearrangements on preimplantation embryonic development potential and molecular karyotype

“…However, there was no significant difference in the fertilization rate, the embryo formation rate on Day3, and blastocyst formation rate among the three groups, suggesting that three types of BCCRs may have some differenteffects on high-quality blastocyst formation but not on embryos formation on Day3. A study showed that compared with exceptional CCRs, there was no significant difference in three-way rearrangements in the high-quality embryo rate on D3 after fertilization, while the former was significantly lower than the latter, which was inconsistent with our results [1] . Another study suggested some three-way complex translocations and complex CCR result in poor embryonic development, and were found to have more mosaicism.…”

“…The application of PGT for BCCR carriers is controversial. Some scholars believedthat PGT is an effective fertility treatment for BCCR carriers, while others opposedit [1,18,19] . Twelve BCCR couples were treated with PGT, and two couples succeeded in getting pregnantand delivered healthy babies.…”

“…Paul et al reported 4 couples, including 3 males and 1 female three-way rearrangements carriers with 6 PGT cycles, who had 6 euploid embryos and 31 aneuploid embryos [10] . Hu L et alreported 7 couples, including 5 couples with three-way rearrangements, who 6 had 3 balanced or normal embryos, 31 abnormal embryos and one embryo of amplification failure, and 1 couple with double two-way translocations, who had no balanced or normal embryos and 12 abnormal embryos [1] . Brunet BCFK et al reported 3 couples with three-way rearrangements with 4 cycles, who had 3 balanced or normal embryos and 15 abnormal embryos, and 1 double two-way translocations who had no balanced or normal embryos and 2 abnormal embryos in one cycle [11] .…”

“…Most of them involve three or more chromosomes and three or more break points. It is very rare in the populationwith approximately 0.5% neonatal morbidity [1,2] . BCCR carriers are rare but varied.…”

“…In addition, male BCCR can also be observed as oligoasthenoterazoospermia and infertile [7,10] . It has been reported that the odds of balanced or normal embryos in couples with BCCR are <6% [1] .Preimplantation genetic testing(PGT) is performed before embryo transfer, and a small portion of cells will be aspirated for comprehensive chromosome screening to analyze embryos identified as balanced or normal for transplantation. The method can reduce the miscarriage rate and improve clinical outcomes [11] .…”