The effect of carrier characteristics and female age on preimplantation genetic testing results of blastocysts from Robertsonian translocation carriers.

PURPOSE

To analyze factors affecting segregation and ploidy results from Robertsonian carriers, and determine chromosomes involved impact chromosome stability during meiosis and mitosis.

METHODS

This retrospective study include 928 oocyte retrieval cycles from 763 couples with Robertsonian translocations undergoing preimplantation genetic testing for structural rearrangements (PGT-SR) using next-generation sequencing (NGS) between December 2012 and June 2020.The segregation patterns of the trivalent of 3423 blastocysts were analyzed according to the carrier's sex and age. A total of 1492 couples who received preimplantation genetic testing for aneuploidy (PGT-A) were included as the control group and matched according to maternal age and testing time stage.

RESULTS

A total of 1728 (50.5%) normal/balanced embryos were identified from 3423 embryos diagnosed. The rate of alternate segregation in male Robertsonian translocation carriers was significantly higher than that in female carriers (82.3% vs. 60.0%, P < 0.001). However, the segregation ratio exhibited no difference between young and older carriers. Further, increasing maternal age decreased the proportion of transferable embryo cycle in both female and male carriers. And the ratio of chromosome mosaic from the Robertsonian translocation carrier group was significantly higher than that in the PGT-A control group (1.2% vs. 0.5%, P < 0.01).

CONCLUSIONS

The meiotic segregation modes were affected by the carrier sex and were independent of the carrier's age. Advanced maternal age decreased the probability of obtaining a normal/balanced embryo. In additional, the Robertsonian translocation chromosome could increase the possibility of chromosome mosaicism during mitosis in blastocysts.