胎儿颈项透明层增厚的产前诊断结果分析

Analysis of fetal nuchal translucency thickening

目的探讨胎儿颈项透明层(nuchal translucency,NT)增厚的产前诊断意义。方法回顾性分析佛山市第一人民医院于2019年1月—2020年10月经超声检查发现NT值≥2.5 mm的143例胎儿及其孕母资料。所有孕妇均为单胎妊娠,于孕11~13~(+6)周测量NT值,并行介入性产前诊断抽取绒毛或羊水进行染色体核型分析和基于微阵列芯片的比较基因组杂交(aCGH)分析。收集、分析孕妇的年龄、胎儿的NT值,以及超声检查结果。计算染色体核型分析和aCGH分析检测出的染色体异常的胎儿例数,并比较各NT值区间G显带分析和aCGH分析检测出的染色体异常的胎儿占比。结果143例孕妇中预产期年龄≥35岁的高龄孕妇20例(14.0%)。143例胎儿的NT值为(3.78±1.49)mm(范围为2.50~8.00 mm),其中129例为单纯NT增厚,经超声检查发现5例合并鼻骨缺失,4例合并脉络丛囊肿,1例合并淋巴水囊瘤,1例合并全身水肿,1例合并多发畸形,1例合并脊柱侧弯,1例合并严重腹裂。染色体核型分析的G显带结果显示,染色体异常胎儿20例(14.0%),其中非整倍体12例(8.4%),包括21-三体综合征11例和18-三体综合征1例;致病性染色体异常8例(5.6%),包括嵌合体3例、染色体不平衡易位2例、染色体平衡易位2例、染色体倒位1例。aCGH分析检出19例(13.3%)染色体异常胎儿,其中非整倍体12例(8.4%),包括21-三体综合征11例和18-三体综合征1例;致病性微缺失、微重复7例(4.9%)。与2.5~<3.0的NT值区间相比,其他NT值区间染色体异常的胎儿占比均显著增高(P值均<0.05)。结论胎儿NT增厚与染色体非整倍体、染色体微缺失和微重复的发生关系密切,随着NT值增加,胎儿染色体异常发生率可能增高。

Objective To explore the significance of fetal nuchal translucency(NT)thickening.Methods Clinical data of 143 fetuses and their pregnant mothers with NT value≥2.5 mm detected by ultrasound at The First People’s Hospital of Foshan from January 2019 to October 2020 were retrospectively analyzed.All pregnant women were singleton pregnancies.NT was measured at 11-13+6 th gestational weeks.Interventional prenatal diagnosis was performed to extract villi or amniotic fluid for chromosome karyotyping and array-based comparative genomic hybridization(aCGH).The age of pregnant women,NT values,ultrasonic results,the number of fetuses with chromosome abnormalities detected by karyotyping and aCGH,and the proportion of fetuses with chromosome abnormalities detected by G-banding analysis and aCGH in each interval of NT value.Results There were 20(14.0%)pregnant women aged≥35 years old.The NT value was(3.78±1.49)mm(range,2.50-8.00 mm).Among the fetuses,129 were simple NT thickening,5 with nasal bone loss,4 with choroid plexus cyst,1 with lymphatic sac tumor,1 with anasarca,1 with multiple deformities,1 with scoliosis and 1 with severe gastroschisis.Chromosome abnormalities were found in 20(14.0%)fetuses by chromosoma1 karyotyping,including 12(8.4%)cases of aneuploidy(11 cases of 21-trisomy syndrome and 1 case of 18-trisomy syndrome)and 8(5.6%)cases of other pathogenic chromosomal abnormalities(3 cases of mosaicism,2 cases of imbalanced chromosome translocation,2 cases of balanced chromosome translocation,and 1 case of chromosome inversion).Chromosome abnormalities were found in 19(13.3%)fetuses by aCGH,including 12(8.4%)cases of aneuploidy(11 cases of 21-trisomy syndrome and 1 case of 18-trisomy syndrome)and 7(4.9%)cases of microdeletion and microrepetition.There were significant differences in the proportion of fetuses with chromosome abnormalities between groups of different NT value intervals(2.5 mm≤NT<3.0 mm group,3.0 mm≤NT<3.5 mm group,3.5 mm≤NT<4.0 mm group and NT≥4.00 mm group,P<0.05),and the incidence of chromosomal abnormalities increased with the increase of NT value.Conclusion Fetal NT thickening is closely related to chromosome aneuploidy,microdeletion and microduplication.The incidence of chromosomal abnormalities increases as the NT value increases.