PGT or ICSI? The impression of NGS-based PGT outcomes in nonmosaic Klinefelter syndrome.

This retrospective study demonstrates the clinical outcomes of patients with nonmosaic Klinefelter's syndrome (KS) who underwent preimplantation genetic testing (PGT) with frozen-thawed testicular spermatozoa. Microdissection testicular sperm extraction (micro-TESE) was performed for sperm retrieval. Next-generation sequencing (NGS) was conducted for embryo analysis. A total of 18 couples aged ≤35 years were included, and 22 oocyte retrieval cycles were completed. Euploidy was detected in 29 of 45 (64.4%) embryos. Additionally, the numbers of aneuploid and mosaic embryos detected were 8 (17.8%) and 8 (17.8%), respectively, regardless of a lack of sex chromosome abnormalities. Finally, 13 couples with euploid embryos completed 14 frozen embryo transfer (FET) cycles. Ten couples had clinical pregnancies, and 6 of them had already delivered 5 healthy babies and 1 monozygotic twin. There were also 4 ongoing pregnancies and 2 biochemical pregnancies, but no early pregnancy loss was reported. Based on our results, we speculate that for KS patients, when sperm can be obtained by micro-TESE, the cryopreservation strategy makes the ovarian stimulation procedure more favorable for female partners. The paternal genetic risk of sex chromosome abnormalities in their offspring is extremely low in men with KS. In addition to PGT, the intracytoplasmic sperm injection (ICSI) procedure is comparably effective but more economical for young nonmosaic KS couples. ICSI should be offered as an option for such couples, but monitoring by prenatal genetic diagnosis is recommended.