CNV-seq及染色体核型分析在染色体异常检测中的比较

Comparative study of copy number variation sequencing and karyotype analysis in detection of chromosome abnormality

目的探讨基因组拷贝数变异测序(copy number variation sequencing,CNV-seq)技术及染色体核型分析在染色体异常检测中的应用价值。方法采用CNV-seq技术和传统的染色体核型分析对42例患者进行染色体分析,对比分析两种检测方法的优势及局限性。结果CNV-seq结果显示,42例标本中染色体拷贝数异常7例,检出率为 16.67%;而染色体核型分析结果显示,存在8例染色体异常(其中染色体结构异常6例,数目异常2例),检出率为 19.04%;此外,还检出4例为染色体多态性变异。结论CNV-seq技术不仅能检测出常规的染色体数目和结构异常(尤其能对来源未知的染色体片段提供更为精准的检测信息),还能检测到100 kb以上的染色体片段的微缺失和微重复;CNV-seq技术不能检测染色体平衡易位和倒位等。传统的染色体核型分析联合CNV-seq检测将会为染色体异常患者提供更为精确的临床诊断。

Objective To explore the clinical application of copy number variation sequencing (CNV-seq) and karyotype analysis in detection of chromosome abnormality. Methods Chromosome of 42 patients was analyzed by karyotype analysis and CNV-seq. The advantages and limitations of the two methods were observed and compared. Results We detected 7 cases of copy number variation by CNV-seq and the case detection rate was 16.67%. We detected cases of chromosomal anomalies by karyotype analysis,which included 6 cases of structural chromosome aberration and 2 cases of chromosome numerical abnormality. The case detection rate of karyotype analysis was 19.04%. Moreover,4 cases of chromosome polymorphism were analyzed. Conclusion CNV-seq can be applied in examining the abnormal chromosome number and structural aberrations,especially in providing clinically significant cytogenetic information that is difficult to be determined by karyotype analysis. It can also analyze chromosome microdeletion and microduplication syndrome with a chromosome resolution of 0.1 Mb. However,CNV-seq fails to identify balanced chromosomal translocation and inversion. Therefore,a combination of karyotype analysis and CNV-seq will provide accurate clinical diagnosis for patients with chromosome abnormality.