70例孤立性胎儿颈项透明层增厚的临床咨询及妊娠结局分析OA

Objective To investigate the genetic etiologies and prognoses of fetuses with isolated increased nu-chal translucency(NT),and to provide evidence for prenatal diagnosis and genetic counseling.Methods This retrospective study enrolled 70 singleton pregnant women who underwent invasive prenatal diagnosis for isolated increased fetal NT at the Prenatal Diagnosis Center,the Affiliated Hospital of Zunyi Medical University from Jan-uary 2024 to April 2025.All cases were divided into four groups based on NT thickness:group 1(≥95th per-centile to＜3.0 mm),group 2(≥3.0 to＜3.5 mm),group 3(≥3.5 to＜4.0 mm),and group 4(≥4.0 mm).Genetic findings and pregnancy outcomes were analyzed.Results The detection rate of fetal chromosomal aneuploidy was 11.43％(8/70),and the rate of pathogenic copy number variations(CNVs)was 5.71％(4/70).CNV sequencing(CNV-seq)identified 4 CNV abnormalities in 62 cases with normal karyotype,yielding an ad-ditional diagnostic yield of 6.45％.Trio-based whole-exome sequencing(trio-WES)was performed in 34 fetuses with normal karyotype and CNV-seq results,and 5 pathogenic gene variants were detected,providing an addi-tional diagnostic yield of 14.71％.The chromosomal abnormality rate was 4.17％(1/24)in the NT＜3.0 mm group and 23.91％(11/46)in the NT ≥3.0 mm group,with a statistically significant difference(P＜0.05).The chromosomal abnormality rate was 25.00％(2/8)in women with advanced maternal age(≥35 years)and 16.13％(10/62)in women＜35 years,with no statistically significant difference(P=0.62).Conclusion For pregnant women who are chromosome negative or have a time limited pregnancy,the detection rate of chromo-some number abnormalities is positively correlated with NT values.It is recommended to use Trio WES testing simultaneously.For patients with isolated NT thickening,regardless of whether they are elderly or not,interven-tional prenatal diagnosis is recommended.