胚胎植入前遗传学检测在性染色体异常夫妇助孕中的应用

Application of Preimplantation Genetic Testing in Assisted Reproductive Therapy for Couples with Sex Chromosome Abnormalities

目的:分析伴有性染色体异常不孕夫妇行植入前遗传学检测(preimplantation genetic testing,PGT)的结局,探讨夫妻双方之一性染色体异常导致胚胎性染色体异常的风险,以及PGT在相关人群中的应用价值。方法:回顾性分析南京医科大学第一附属医院生殖医学科伴有性染色体异常同时行PGT治疗的夫妇的胚胎染色体检测结果以及胚胎移植结局。PGT策略采用囊胚期活检,活检材料经过全基因组扩增后,采用全基因组低深度测序分析染色体拷贝数改变。在复苏周期中,统计可移植胚胎移植后的临床妊娠结局。结果:在性染色体异常的23对夫妇(其中包括47,XYY及其嵌合体6例、47,XXY及其嵌合体2例、47,XXX 4例、45,X嵌合体8例、女性X染色体节段性缺失3例)的24个促排卵周期中,共获得可检测囊胚77枚,明确诊断76枚(98.70%),其中40枚(52.63%)为整倍体可移植胚胎,13枚(17.10%)非整倍体嵌合体胚胎,23枚(30.26%)为非整倍体不可移植胚胎。在3例X染色体节段性缺失患者中所有异常胚胎均为X染色体节段性缺失,而其他性染色体数目异常患者中共发现3枚(3.95%)性染色体嵌合体非整倍体胚胎。在18个复苏移植周期中,共获得9例(50.00%)健康活产。结论:性染色体数目非整倍体异常夫妇的胚胎性染色体异常风险较低,在辅助生殖技术助孕过程中PGT并不是必需的治疗方案;而性染色体节段性非整倍体夫妇胚胎性染色体异常风险较高,结合卵巢功能情况以及在患者充分知情同意的情况下,可酌情考虑PGT,降低后代性染色体异常风险。

Objective: To analyze the outcomes of preimplantation genetic testing(PGT) in infertile couples with sex chromosome abnormalities and to explore the risk of embryo sex chromosome abnormalities, so as to evaluate the application value of PGT in the related populations. Methods: The embryo chromosome and embryo transfer outcomes of couples with sex chromosome abnormalities treated with PGT were analyzed retrospectively.The whole genome low depth sequencing was used to analyze the alterations of chromosomal copy number after whole genome amplification of biopsy material from the blastocyst stage. In the freeze-thaw cycles, the clinical pregnancy outcomes of embryo transfer were calculated. Results: A total of 77 detectable blastocysts were obtained in 24 controlled ovulation stimulation cycles from 23 couples with sex chromosome abnormalities, including 6 couples with 47,XYY and mosaicism, 2 couples with 47,XXY and mosaicism, 4 couples with 47,XXX, 8 couples with 45,X mosaicism, 3 couples with X-chromosomal segmental aneuploidy. In 77 detectable blastocysts, 76(98.70%) were definitively diagnosed, including 40(52.63%) euploid, 13(17.10%) mosaic embryos and 23(30.26%) completely aneuploid embryos. All of abnormal embryos were X-chromosomal segmental aneuploidy in the 3 patients with X-chromosomal segmental aneuploidy;whereas a total of 3(3.95%) sex chromosome mosaic aneuploidies were found in the couples with the other sex chromosome numerical abnormality. Nine(50.00%)healthy live births were obtained during a total of 18 freeze-thaw cycles. Conclusions: The couples with sex chromosome numerical aneuploidy have a low risk of embryonic sex chromosome abnormalities, and PGT is not an essential treatment option;whereas the couples with sex chromosome segmental aneuploidy are at high risk of embryonic sex chromosome abnormalities, and PGT may be considered in combination with ovarian function profile and adequate informed consent from the patients, reducing the risk of sex chromosome abnormalities in offspring.