性染色体非整倍体异常的产前诊断和妊娠结局分析OA

Objectives:To analyze the clinical characteristics of abnormal karyotypes of fetal sex chromosome aneuploidy(SCA)in 337 cases and clarify the correlation between different prenatal diagnosis indications and abnormal SCA karyotypes. Methods:A total of 20 861 patients who underwent chromosome karyotype analysis of amniotic fluid at the Prenatal Diagnosis Center of Beijing Obstetrics and Gynecology Hospital from January 2019 to December 2023 were enrolled,among whom 337 cases with abnormal SCA karyotypes were identified.The karyotype distribution and pregnancy outcomes of SCA cases under different diagnosis indications were compared. Results:A total of 337 cases with abnormal SCA karyotypes were detected among the 20 861 prenatal diagnosis cases,with a detection rate of 1.62％,including 78 cases of sex chromosome mosaicism.Among the 337 SCA cases,the most common prenatal diagnosis indication was abnormal sex chromosome results indicated by non-invasive prenatal testing(NIPT)(236 cases,accounting for 70.03％),followed by advanced maternal age(53 cases,accounting for 15.73％).Among the 78 cases of sex chromosome mosaicism,43 cases(55.13％)presented abnormal NIPT results and 17 cases(21.79％)were of advanced maternal age.A follow-up was conducted on the pregnancy outcomes of 337 fetuses with SCA:among 116 fetuses with 47,XXY,13 cases were delivered,with a live birth rate of 11.20％;among 64 fetuses with 47,XXX,33 cases were delivered,with a live birth rate of 51.56％;among 54 fetuses with 47,XYY,30 cases were delivered,with a live birth rate of 55.56％;all 16 fetuses with complete 45,X underwent induced labor;among the 78 cases of mosaicism,43 cases were delivered,with a live birth rate of 55.13％.Among the 78 fetuses diagnosed with sex chromosome mosaicism,60.26％(47/78)were verified by two-way confirmation of karyotype combined with fluorescence in situ hybridization(FISH)or copy number variation sequencing(CNV-seq). Conclusions:SCA is a common type of chromosomal abnormality in prenatal diagnosis,and its detection is closely associated with abnormal NIPT results and advanced maternal age.There are significant differences in pregnancy outcomes among different types of SCA.The results of this study can provide important data support for clinical genetic counseling.