目的 探讨发育障碍疾病患儿致病性拷贝数变异（CNV）的特征。方法 收集2017至2019年诊断为发育迟缓、 并经核型分析患儿的临床资料，采集患儿外周血进行基于高通量测序的低深度全基因组测序（CNV-seq）。利用ClinVar、 DECIPHER、OMIM、DGV数据库注释CNV数据，依据ACMG评估CNV致病性，并通过PubMed数据库检索相关报道文献。 结果 检测90例患儿，CNV阳性18例，阳性率为20 %。其中ACMG判定致病性，或有报道的致病性CNV 15例，可能致病 CNV 3例；意义未明的CNV 32例。结论 CNV是导致儿童发育迟缓的重要病因，>1 Mb的微缺失/重复具有更高致病性， 可将CNV-seq作为产前诊断的重要手段，以有效防治发育障碍相关疾病。

Objective? To detect copy number variation sequencing (CNV) in children diagnosed with developmental delay (DD). Methods? Clinical data of children diagnosed with DD in Shanxi Provincial Children's Hospital (Shanxi Maternal and Child Health Hospital) from 2017 to 2019 were collected, and all patients had karyotype tested. CNV-seq was used to detect CNVs in these patients. ClinVar, DECIPHER, OMIM, DGV and other databases were used as references for data annotation, and the pathogenicity of CNV is classified according to ACMG guideline. Related articles were retrieved through the PubMed database. Results? Ninety patients were tested and the diagnostic rate was 20% ( 18/ 90 ). In which 15 patients were found have pathogenic CNVs,and three patients were found have likely pathogenic CNV. In addition, 32 patients carried copy number variation of unknown significance. Conclusion? This study confirmed that CNVs were an important cause of DD, and the CNVs > 1Mb in length are more likely pathogenic. In view of this, we recommend that CNVs testing be the first-line test in children with DD. CNV-Seq is a more efficient CNVs detection method based on high-throughput sequencing.