摘要目的:评估低深度全基因组拷贝数变异测序技术(copy number variation sequencing，CNV-seq)在不明原因智力低下/发育迟缓(mental retardation/developmental delay, MR/DD)患者遗传病因中的诊断作用。方法:选择2017年11月至2018年12月在郑州大学第一附属医院遗传与产前诊断中心就诊的145例MR/DD患者作为研究对象，采集外周血样本进行全基因组测序，联合生物信息学手段分析MR/DD患者所携带的拷贝数变异(copy number variations，CNVs)相关信息。结果:145例MR/DD患者中检出49例有基因组CNVs，共发现67个CNVs，CNVs平均长度为5.27 Mb。通过评估，22例患者携带与MR/DD相关的CNVs，涉及21种综合征，涵盖174个智力低下相关基因，分布于10条染色体的18个不同区段。CNV-seq在不明原因MR/DD患者中发现携带与疾病相关的CNVs的诊断率为15.17%(22/145例)。结论:基因组CNVs相关的微缺失/重复是不明原因MR/DD患者的遗传学病因之一，全基因组CNV-seq技术可为MR/DD患者提供准确的遗传学病因的诊断。

abstractsObjective:To detect genomic copy number variations (CNVs) among 145 children with unexplained mental retardation/developmental delay (MR/DD) by using low-depth whole-genome copy number variation sequencing (CNV-seq).Methods:Peripheral blood samples were collected from the patients and subjected to DNA extraction and CNV-seq. The results were analyzed by a combination of bioinformatic tools.Results:Forty-nine patients were found to carry a total of 67 CNVs with an average size of 5.27 Mb. Among these, 22 patients were assessed to carry MR/DD-related CNVs involving 21 syndromes. This gave a diagnostic rate of 15.17%(22/145) for CNVs associated with unexplained MR/DD. The corresponding regions of the 22 MR/DD-related CNVs in the human genome covered 174 MR/DD-related pathogenic genes, which have mapped to 18 sections on 10 chromosomes.Conclusion:Genomic CNVs-related microdeletions/duplications account for a significant proportion of unexplained MR/DD, for which CNV-seq can provide an accurate diagnosis.