目的　探讨致共济失调毛细血管扩张症的ATM基因新突变的致病性。方法　分析2个无血缘关系的共济失 调毛细血管扩张症家系成员的临床资料及基因检测结果，并应用Sanger测序对新突变位点进行验证。结果　家系1先证 者为男性，11岁，家系2先证者为女性， 8岁。均有共济失调毛细血管扩张症的典型表现，甲胎蛋白升高。头颅磁共振成像 示小脑萎缩。家系1先证者发现c.7627delA与c.8385-8394del复合杂合突变，分别遗传自父母；家系2先证者发现c.2638delG 与c.2921+1G>C复合杂合突变，c.2638delG来源于母亲，其父ATM基因不详。经HGMD检索， 4个变异目前均未见有文 献报道，为新突变。 4个新突变经蛋白功能分析软件预测等确认为致病突变。结论　证实ATM基因新突变为2个无关的共 济失调毛细血管扩张症家系的致病原因。

　Objective　To investigate the pathogenicity of novel mutations in the ATM gene that cause ataxia telangiectasia. Methods　The clinical data and gene detection results of two unrelated autistic telangiectasia pedigree family were analyzed, and new mutation sites were verified by Sanger sequencing. Results　Compound heterozygous mutations of c.7627delA and c.8385-8394del were found in the proband of family 1 which were inherited from the parents, and compound heterozygous mutation c.2638delG and c.2921+1G>C were found in the proband of family 2. In family 2, c.2638delG is inherited from the mother, while the paternal sample is not available. These four novel mutations have not been documented in HGMD database. In silico analysis it predicted the four mutations were pathogenic. Conclusion　The novel mutations in ATM gene were confirmed to be the cause of the two unrelated ataxia telangiectasia families.