无创产前基因检测筛查胎儿性染色体异常的临床意义

Clinical significance of non-invasive prenatal genetic testing in screening fetal sex chromosome abnormalities

目的回顾性分析无创产前基因检测对于胎儿性染色体异常的筛查价值。方法回顾性选取赣州市妇幼保健院妇产科2018年1月至2019年12月开展无创产前基因检测筛查的17561例单胎孕妇作为研究对象,根据年龄分为<30岁组、30~<35岁组、35~<38岁组、≥38岁四组,比较各组间胎儿性染色体非整倍体的发生率及妊娠结局。结果17561例孕妇中,93例(0.53%)无创产前基因检测诊断胎儿性染色体异常高危,其中胎儿性染色体数目异常高危的有87例,染色体结构异常5例,阳性率为0.53%,其中44例为45,X高危,19例为47,XXY高危,18例为47,XXX高危[其中6例为母体47,XXX高危(占比33.33%)],6例为47,XYY高危(占比38.89%)。性染色体高危孕妇均接受羊水穿刺细胞核型分析,经产前咨询,知情同意。45,X、47,XXX、47,XXY、47,XYY阳性预测值分别为92.31%、88.89%、88.89%、75.00%。年龄35~<38岁、≥38岁的胎儿45,X发生率低于<30岁组,年龄35~<38岁的胎儿45,X发生率低于30~<35岁组,差异有统计学意义(P<0.008)。≥38岁组47,XXX发生率高于30~<35岁组,差异有统计学意义(P<0.008);35~<38岁、≥38岁组47,XXY发生率高于<30岁组,差异有统计学意义(P<0.008);各组间胎儿47,XYY发生率比较,差异无统计学意义(P>0.05);≥38岁、35~<38岁组胎儿性染色体三体的总发生率高于<30岁组,差异有统计学意义(P<0.008)。结论筛查胎儿性染色体异常时采用无创产前基因检测的准确率较高,能够保证胎儿性染色体异常检出率得到提升,值得在临床推广应用。减少性染色体异常胎儿的出生,减少有创性产前诊断。孕妇年龄越大,胎儿45,X发生风险降低,但47,XXX和47,XXY的发生风险升高。

Objective To retrospectively analyze the screening value of non-invasive genetic testing for fetal sex chromosome abnormalities.Methods A total of 17561 singleton pregnant women who carried out non-invasive prenatal genetic testing and screening in the Department of Obstetrics and Gynecology of Ganzhou Maternal and Child Health Hospital from January 2018 to December 2019 were retrospectively selected as research objects.They were divided into<30 years old group,30-<35 years old group,35-<38 years old group and≥38 years old group according to their age.The incidence of fetal sex chromosome aneuploidy and pregnancy outcome were compared between the groups.Results Among 17561 pregnant women,93 cases(0.53%)were diagnosed as high risk of fetal sex chromosome abnormalities by non-invasive prenatal genetic testing,including 87 cases with abnormal number of fetal sex chromosomes,5 cases with abnormal chromosome structure,and the positive rate was 0.53%,of which 44 cases were high risk of 45,X,19 cases were high risk of 47,XXY,and 18 cases were high risk of 47,XXX(of which 6 cases were high risk of maternal 47,XXX[33.33%])and 6 cases were high risk of 47,XYY(38.89%).All pregnant women with high-risk sex chromosome underwent amniocentesis,karyotype analysis,prenatal consultation and informed consent.The positive predictive values of 45,X,47,XXX,47,XXY,47,XYY were 92.31%,88.89%,88.89%and 75.00%respectively.The incidence of 45, X in 35-<38 years old group and ≥38 years old group was lower than that in <30 years old group, the incidence of 45, X in 35-<38 years old group was lower than that in 30-<35 years old group, the differences were statistically significant (P<0.008). The incidence of 47, XXX in ≥38 years old group was higher than that in 30-<35 years old group, the difference was statistically significant (P<0.008). The incidence of 47, XXY in 35-<38 years old group and ≥38 years old group was higher than that of <30 years old group, the difference was statistically significant (P<0.008). There was no significant difference in the incidence of 47, XYY among the groups (P>0.05). The incidence of total sex chromosome trisomy in ≥38 years old group and 35-<38 years old group was higher than that in <30 years old group, the difference was statistically significant (P<0.05). Conclusion The accuracy of non-invasive prenatal genetic testing in screening fetal sex chromosome abnormalities is high, which can ensure the improvement of the detection rate of fetal sex chromosome abnormalities, and is worthy of clinical application. Reduce the birth of fetuses with sex chromosome abnormalities and invasive prenatal diagnosis. The older the pregnant woman, the lower the risk of fetal 45, X, but the higher the risk of 47, XXX and 47, XXY.