Monash IVF, Suite 1, 252 Clayton Rd, Clayton, VIC, 3168, Australia.
J Assist Reprod Genet. 2017 Nov;34(11):1483-1492. doi: 10.1007/s10815-017-1009-0. Epub 2017 Jul 29.
For translocation carriers, preimplantation genetic diagnosis (PGD) provides the opportunity to distinguish between normal/balanced and unbalanced embryos prior to implantation and, as such, increases the likelihood of a successful ongoing pregnancy. The data presented here compares autosomal reciprocal and Robertsonian translocation segregation patterns in day 3 versus day 5/6 IVF-PGD embryos to determine if there is a difference in the chromosome segregation patterns observed at these developmental time points.
A retrospective analysis on PGD translocation carriers at Monash IVF was performed. Segregation patterns were compared between day 3 and day 5/6 embryos to ascertain whether selection against malsegregants exists.
For reciprocal translocations, 1649 day 3 embryos (139 translocations) from 144 couples and 128 day 5/6 embryos (59 translocations) from 60 couples were analysed. Day 3 segregation analysis showed that 22.3% of embryos were normal/balanced (consistent with 2:2 alternate segregation) and 77.7% were unbalanced (malsegregation). Day 5/6 segregation analysis showed that 53.1% of embryos were normal/balanced and 46.9% were unbalanced. For Robertsonian translocations, 847 day 3 embryos (8 translocations) from 54 couples and 193 day 5/6 embryos (6 translocations) from 31 couples were analysed. Day 3 segregation analysis showed that 38.7% of embryos were normal/balanced (consistent with 2:1 alternate segregation) and 61.3% were unbalanced. Day 5/6 segregation analysis showed that 74.1% of embryos were normal/balanced and 25.9% were unbalanced.
This data demonstrates an increase in the proportion of genetically normal/balanced embryos at day 5/6 of development. This suggests a strong natural selection process between day 3 and day 5/6 in favour of normal/balanced embryos. These findings support performing PGD testing on day 5/6 of embryo development.
对于易位携带者，胚胎植入前遗传学诊断（PGD）提供了在植入前区分正常/平衡和不平衡胚胎的机会，从而增加了成功进行妊娠的可能性。本文比较了第 3 天和第 5/6 天体外受精 - PGD 胚胎中常染色体相互易位和罗伯逊易位的分离模式，以确定在这些发育时间点观察到的染色体分离模式是否存在差异。
对 Monash IVF 的 PGD 易位携带者进行了回顾性分析。比较第 3 天和第 5/6 天胚胎的分离模式，以确定是否存在对错误分离的选择。
对于相互易位，分析了 144 对夫妇的 1649 个第 3 天胚胎（139 个易位）和 60 对夫妇的 128 个第 5/6 天胚胎（59 个易位）。第 3 天的分离分析显示，22.3%的胚胎为正常/平衡（与 2:2 交替分离一致），77.7%为不平衡（错误分离）。第 5/6 天的分离分析显示，53.1%的胚胎为正常/平衡，46.9%为不平衡。对于罗伯逊易位，分析了 54 对夫妇的 847 个第 3 天胚胎（8 个易位）和 31 对夫妇的 193 个第 5/6 天胚胎（6 个易位）。第 3 天的分离分析显示，38.7%的胚胎为正常/平衡（与 2:1 交替分离一致），61.3%为不平衡。第 5/6 天的分离分析显示，74.1%的胚胎为正常/平衡，25.9%为不平衡。
这些数据表明，在发育的第 5/6 天，正常/平衡胚胎的比例增加。这表明在第 3 天和第 5/6 天之间存在强烈的自然选择过程，有利于正常/平衡的胚胎。这些发现支持在胚胎发育的第 5/6 天进行 PGD 检测。
