染色体微阵列分析技术分析22例先天性唇腭裂畸形患者

Analysis of 22 patients with congenital cleft lip and palate using high-resolution chromosome microarray

目的应用染色体微阵列分析技术（chromosomem icroarray analysis，CMA）在全基因组水平分析先天性唇腭裂患者的遗传学病因。方法选取先天性唇腭裂畸形患者22例（单纯性唇裂患者8例，单纯性腭裂患者4例，单纯性唇腭裂患者7例，唇腭裂合并先天性心脏病患者3例），常规G显带染色体核型分析均未发现异常。按照美国Affymetrix公司CytoScan^TM HD芯片的标准操作流程对患者外周血DNA分别进行CMA检测，并通过配套的计算机软件及生物信息学分析结果。结果全部22例患者均存在基因组DNA拷贝数变异（copy number variation，CNV），每例患者基因组含有2～9个100kb到1．8Mb不等的CNVs。在5例患者中检出高度可疑的致病性CNVs，占22．7％（5／22）。其中，单纯性腭裂患者可疑致病性CNVs的检出率为50％（2／4），单纯性唇腭裂患者检出率为14．3％（1／7），唇腭裂合并先天性心脏病患者检出率为66．7％（2／3）。可疑致病性CNVs涉及的染色体片段分别为：8p23．1；10q22．2-q22．3；18q12．3；20p12．1以及6q26。其中，10q22．2-q22．3区域中的MYST4基因，20p12．1区域中的MACR0192基因以及8p23．1区域中的SOX7基因是新发现的先天性唇腭裂可疑致病基因。结论CMA技术可以显著提高先天性唇腭裂遗传学病因的检出率，并且具有识别新的可疑致病基因的能力。对于常规G显带染色体核型分析未见异常的先天性唇腭裂患者，建议进一步行CMA技术分析。合并有其他先天性结构异常的唇腭裂患者，其基因组发生不平衡变异的风险显著增高。

Objective To assess the value of chromosome microarray analysis （CMA） for identifying the etiology of patients with congenital cleft lip and palate. Methods Twenty-two patients with no identifiable chromosomal aberrations by conventional cytogenetic technique were selected. DNA was extracted and hybridized with Affymetrix CytoScan^TM HD arrays following the manufacturer＇s protocol. The data were analyzed with a CHAS v2.0 software. Results CMA analysis has identified submicroscopic copy number variants （CNVs） in all of the cases, which have ranged from 100 kb to 1. 8 Mb. Potential pathogenic CNVs were identified in 5 patients （22. 7o//00）, which involved microdeletions and microduplieations on 8p23. 1, 10q22. 2-q22. 3, 6q26, 20p12. 1 and 18q12. 3. MYST4, MACROD2 and SOX7 genes are likely the causative genes. Conclusion CMA is an effective method for identification of etiology in patients with cleft lip and palate. CMA should be provided for patients with cleft lip and palate but a normal karyotype. Especially for those with additional structural abnormalities, there is a high risk for submicroscopic chromosomal aberrations.