[Effect of complete Y chromosome AZFc microdeletion on embryo euploidy]

Preimplantation genetic testing (PGT) was performed to analyze the embryo euploidy in patients with complete Y chromosome AZFc microdeletion.

The clinical data of complete AZFc microdeletion underwent PGT from January 2013 to December 2021 in Reproductive Medicine Center of the First Affiliated Hospital of Nanjing Medical University were retrospectively analyzed. The patients with monogenic disease who underwent PGT during the same period were set as the control group. The basic characteristics, fertilization rate, Day 3 high quality embryo rate, blastocyst formation rate, embryo euploid rate, 45, X embryo ratio was compared between the two groups.

A total of 220 patients were included, including 91 patients with complete AZFc microdeletion and 129 patients with monogenic disease. There was no significant difference in age between the two groups. In semen parameters, the sperm concentration, total sperm count and progressive motility in AZFc microdeletion group were lower than those in monogenic disease group, and the differences were statistically significant (P=0.001). The fertilization rate of AZFc microdeletion group was lower than that in monogenic disease group (P=0.012), and there was no significant difference in the number of MII oocytes, Day 3 high-quality embryo rate and blastocyst formation rate. A total of 933 blastocysts were successfully tested, including 496 blastocysts in AZFc deletion group and 437 blastocysts in monogenic disease group. The euploid, aneuploid and mosaic rates of the AZFc microdeletion group were 57.26%, 24.60% and 18.14%, respectively, while those of the monogenic disease group were 66.13%, 23.80% and 10.07%, with statistically significant differences between the two groups (P=0.001). Further analysis of the two groups of aneuploid embryos showed that aberrations occurred most commonly in chromosome16 (3.87%), X (3.46%), 13 (2.44%), 22 (2.24%) and 19 (2.03%) in AZFc microdeletion group, respectively, while the monogenic disease group was 22 (4.35%), 16 (2.97%), 7 (2.74%), 15(1.60%) and 2(1.60%), respectively. The proportion of sex chromosome abnormality in AZFc microdeletion group was higher than that in monogenic disease group (P=0.039), and there was no significant difference in the proportion of 45,X between the two groups.

Compared with monogenic disease group, The embryo euploid rate in AZFc microdeletion patients decreased and the proportion of 45, X embryos did not increase significantly. It is recommended to select euploid female embryos by PGT, which not only avoids vertical transmission of AZFc microdeletion, but also reduces the risk of miscarriage due to aneuploid embryos.