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| Clinical value of SNP array in prenatal diagnosis of fetus with increased nuchal translucency |
| ZHOU Lili, WEN Zhengjing, XU Chenyang, LI Huanzheng, XU Xueqin, TANG Shaohua |
| The Clinical Laboratory of Wenzhou Central Hospital, Wenzhou 325000, China |
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| Cite this article: |
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ZHOU Lili,WEN Zhengjing,XU Chenyang, et al. Clinical value of SNP array in prenatal diagnosis of fetus with increased nuchal translucency[J]. JOURNAL OF WEZHOU MEDICAL UNIVERSITY, 2021, 51(1): 19-24.
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Abstract Objective: To investigate the clinical value of SNP array analysis in prenatal diagnosis of fetuses
with increased nuchal translucency. Methods: A total of 220 fetus with increased NT (NT≥2.5 mm) were tested by SNP array and conventional karyotyping. Results: Chromosomal abnormality was identified in 14.5% (32/220) fetus, with aneuploidy accounting for 87.5% and structural alterations accounting for 12.5%. Among them trisomy 21 was the most common (43.8%), followed by trisomy 18 (21.9%). Infetuses with normal karyotype, SNP array detected another nine cases with abnormal CNVs, of which five cases were pathogenic CNVs and four cases were likely pathogenic CNVs. The fetuses were classified into three groups according to NT thickness 2.5-2.9 mm, 3.0-3.4 mm and ≥3.5 mm, with the abnormal karyotype rate being 5.6%, 7.9% and 23.3% respectively and the abnormal SNP array rate being 5.6%, 11.1% and 30.1% respectively. The chromosome abnormality rate increased significantly with the increase of NT thickness. The application of SNP array analysis for fetuses with increased NT (≥3.5 mm) could detect another seven abnormal CNVs, improving the genetic etiology rate by 6.8%, which had statistical difference compared with chromosomal karyotype (P<0.05). However, there was no statistical difference when NT thickness was 3.0-3.4 mm. Conclusion: NT thickness is correlated with chromosome abnormality in that fetal chromosomal abnormal rate increases significantly with the increase of NT thickness. The application of SNP array analysis for fetuses with increased NT (≥3.5 mm) in prenatal diagnosis could improve
the genetic etiology rate by 6.8%, which is of great value to clinical genetic counseling.
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