基于染色体核型分析及单核苷酸多态性基因芯片技术的脐静脉血产前诊断分析

Prenatal diagnosis of umbilical venous blood by karyotype analysis and single nucleotide polymorphism array technology

目的总结具有产前诊断指征的孕妇脐静脉血染色体核型分析特点,并探讨染色体核型分析及单核苷酸多态性微阵列基因芯片(SNP-array)技术在脐静脉血产前诊断中的应用价值。方法选取有产前诊断指征的4843例孕妇,在B超引导下抽取脐静脉血进行G显带染色体核型分析,其中2986例孕妇同时行SNP-array检测。比较两种检测方法对染色体异常的检出情况。结果4843例脐血标本中,共检出染色体核型异常288例(5.95%),以常染色体三体为主;在同时行SNP-array检测的2986例标本中,染色体核型分析提示核型异常203例(6.80%),其中有46例(22.66%)、5例(2.46%)分别来源于2568例SNP-array检测正常及156例SNP-array检测为临床意义不明确变异的标本。SNP-array共检出262例(8.77%)存在致病性拷贝数变异,其中106例(3.91%)来自2714例染色体核型正常的标本。染色体核型分析和SNP-array检测联合应用的异常检出率为10.48%(313/2986),高于两者单独的异常检出率(均P<0.05)。结论常染色体三体是最为常见的染色体核型异常,仍是今后监测的重点项目之一。染色体核型分析及SNP-array技术各有优缺点,联合应用可有效地提高脐静脉血产前诊断染色体异常检出率。

Objective To summarize the features of karyotype analysis of umbilical venous blood in pregnant women with indicators of prenatal diagnosis,and to explore the application value of karyotype analysis and single nucleotide polymorphism microarray(SNP-array)technology in prenatal diagnosis of umbilical venous blood.Methods A total of 4843 pregnant women with indicators of prenatal diagnosis were selected and received G-banding karyotype analysis after umbilical venous blood collecting under B-ultrasound,of which 2986 pregnant women were detected by SNP-array simultaneously.The findings of the two detection approaches for chromosome abnormalities were compared.Results In 4843 samples of umbilical blood,288(5.95%)samples were identified as abnormal karyotypes,with autosomal trisomy as the dominant abnormality;in 2986 samples simultaneously detected by SNP-array,203(6.80%)samples were diagnosed as abnormal karyotypes by karyotyping,of which 46(22.66%)samples and 5(2.46%)samples were identified from 2568 samples with negative SNP-array detection and 156 samples diagnosed as variant of uncertain clinical significance by SNP-array,respectively.About 262(8.77%)samples were diagnosed as pathogenic copy number variations by SNP-array,of which 106(3.91%)samples were from 2714 samples with normal karyotypes.The abnormality detection rate of the combined application of karyotype analysis and SNP-array detection was 10.48%(313/2986),and higher than the rate of either of them(all P<0.05).Conclusion Autosomal trisomy is the most common karyotype abnormality and remains a key item for future monitoring.Karyotype analysis and SNP-array technology have pros and cons,and their combined application can effectively raise the chromosome abnormality detection rate in prenatal diagnosis of umbilical venous blood.