Journal of International Reproductive Health/Family Planning ›› 2022, Vol. 41 ›› Issue (5): 360-364.doi: 10.12280/gjszjk.20220224

• Original Article • Previous Articles     Next Articles

Application of Chromosome Karyotype Analysis and CNV-Seq in Fetals with Increased Nuchal Translucency

HU Yan-ping, YUAN Jing(), LI Qin, ZHOU Pei, CHENG Long-feng   

  1. Prenatal Diagnosis Center, The First Affiliated Hospital of Anhui Medical University, Hefei 230022, China
  • Received:2022-04-26 Published:2022-09-15 Online:2022-10-12
  • Contact: YUAN Jing E-mail:yuanjing_ahmu@163.com

Abstract:

Objective: To summarize the application of chromosome karyotype analysis combined with copy number variation sequencing (CNV-seq) in the fetuses with increased nuchal translucency (NT). Methods: Karyotype analysis and CNV-seq were performed in 189 singleton fetuses with NT≥2.5 mm and gestation weeks from 11 to 13+6, and the detection rate of chromosomal abnormalities was analyzed. According to the pre-interventional diagnosis indications, they were divided into the simple NT thickening group (n=119) and the non-simple NT thickening group (n=70). According to the NT thickness, they were divided into the 2.5 mm≤NT<3.5 mm group (n=123) and the NT≥3.5 mm group (n=66). Results: Karyotype analysis revealed 31 cases (16.40%) of chromosome abnormalities, including 24 cases (12.70%) of aneuploidy and 7 cases (3.70%) of structural abnormalities, and CNV-seq revealed 38 cases (20.11%) of pathogenic copy number variations (pCNVs), including 24 cases (12.70%) of aneuploidy and 14 cases (7.41%) of other pCNVs. Nine additional cases (5.70%) of pCNVs were detected by CNV-seq in fetuses with normal karyotype. The detection rates of pCNVs and chromosome aneuploidy in the non-simple NT thickening group were higher than those in the simple NT thickening group, and the differences were statistically significant (P<0.05). There was no significant difference in the detection rates of other pCNVs (P>0.05). The detection rates of pCNVs and chromosome aneuploidy in the NT≥3.5 mm group were higher than those in the 2.5 mm≤NT<3.5 mm group, the differences were statistically significant (P<0.05). There was no significant difference in the other pCNVs detection rates (P> 0.05). Conclusions: Fetal chromosomal abnormalities were increased with NT thickening or other pre-interventional diagnostic indicators, but they were not significantly associated with other pCNVs. CNV-seq combined karyotype analysis can help to detect the different types of chromosomal abnormalities, to avoid the missed diagnosis of chromosomal structural abnormalities and chromosomal microdeletion/microduplication.

Key words: Incresed nuchal translucency, Chromosomes, Karyotyping, Sequence analysis, DNA copy number variations, Fetus, Prenatal diagnosis