基于高通量测序的染色体组拷贝数分析技术在流产胚胎组织遗传学诊断中的应用价值

Application of copy number variation analysis based on next-generation sequencing in the genetic analysis of missed abortion chorionic villi

目的探讨基于高通量测序的染色体组拷贝数分析（NGS—CNVA）技术在流产胚胎组织遗传学诊断中的价值。方法选择2012年8月至2014年5月间在北京市海淀区妇幼保健院确诊为稽留流产的患者74例（孕6～13周），对其流产组织物行绒毛染色体核型分析和NGS—CNVA；对NGS．CNVA结果进行染色体核型的复核，比较两种诊断方法的不同临床应用特点。结果（1）74例患者绒毛染色体核型分析的分辨率均在320条带左右，获得结果的时间平均为22d，染色体核型分析结果正常30例，染色体数目异常26例，染色体结构异常18例。（2）74份样本均获得NGS．CNVA的有效结果，获得结果的时间为7，10d。（3）染色体核型分析结果正常或数目异常的56例患者中，NGS—CNVA结果与染色体核型分析结果一致、未发现基因拷贝数变异（CNV）者有28例（28／56，50％），发现CNV〈10Mb的重复或缺失19例（19／56，34％），NGS—CNVA中发现CNV≥10Mb的重复或缺失诊断不符9例（16％，9／56）。（4）再次行染色体核型分析并复核结果，30例染色体核型分析结果正常者中有7例CNV〈10Mb的重复或缺失，3例CNV≥10Mb的重复或缺失。（5）染色体核型分析结果为染色体结构异常者18例，复核染色体结果，其中罗氏易位6例，通过NGS—CNVA技术能明确提示染色体缺失或重复片段的具体区域；8例染色体结构异常的诊断仍不明确者，NGS-CNVA结果可协助确定区带、明确诊断，但不能提示染色体的空间位置。结论NGS-CNVA技术与传统染色体核型分析技术比较，其实验失败率低，标本要求低，染色体分辨率高，获得结果的时间早。NGS—CNVA技术可以作为流产组织物遗传学诊断的方法之一，具有较好的临床应用价值。

Objective To investigate the value of copy number variation analysis based on next-generation sequencing （NGS-CNVA） in the genetic analysis of missed abortion chorionic villi. Methods From August 2012 to May 2014, chorionic villi from 74 cases of missed abortion at 6- 13 gestational weeks in Haidian Maternal and Child Health Hospital were collected and analyzed by karyotype analysis and NGS-CNVA. The results of the two methods were compared. Results （1） Karyotype analysis was carried out for the villi from the 74 missed abortion patients. Thirty cases were euploid, 26 cases were aneuploid, while 18 cases had structural abnormalities. The resolution of the karyotyping was 320 bands and the average report time was 22 days. （2） All of the 74 samples obtained NGS-CNVA results and the report time was 7-10 days. （3） The NGS-CNVA results of 56 cases were consistent with karyotype. Among them, 28 cases （28/56, 50%） had no copy number variants （CNV）, and 19 cases （19/56, 34%）had CNV between 1 Mb and 10 Mb. 9 cases （9/56,16%） had CNV ≥10 Mb found by NGS-CNVA, but not found by karyotyping. （4） According to the results of NGS-CNVA, karyotype were reviewed. The reviewed results found 7 cases with CNV〈10 Mb and 3 cases with CNV≥10 Mb in 30 cases which got normal karyotype results at the first analysis. （5） Among the 18 cases of structural abnormalities, 6 cases were Robertsonian translocation. Sequencing technology could confirm the specific area of chromosome deletion/duplication in 8 cases, but could not locate them. Conclusions NGS-CNVA has lower failure rate, higher resolution, lower specimen requirement and shorter report time than karyotype analysis when used for the genetic analysis of missed chorionic villi. NGS-CNVA could be a useful genetic analysis method for the missed abortion villi.