中文摘要：

目的通过对一个蒙古族非综合征型先天缺失牙家系转录调控因子成对盒基因PAX9（paired box 9）突变进行检测，为蒙古族该病发病的分子机制提供理论依据。方法收集17名蒙古族非综合征型先天缺失牙家系主要成员的外周血（其中健康者9名，患者8例），采用PCR结合DNA测序技术对患者进行PAX9基因突变检测和分析。结果该家系8例患者的PAX9基因外显子4的87位点发生了单碱基改变C．87G〉C，即G／C杂合，而家系中9名健康者均为C纯合，与GenBank健康人参考序列一致（登录号：NC_000014）。结论PAX9基因外显子4的C．87G〉C（P．Ala240Pro）改变可能是导致该蒙古族非综合征型先天缺失牙家系发病的主要原因。

英文摘要：

Objective To investigate the mutation in transcription factor paired box gene PAX9 in a mongolian family with non-syndromie oligodontia. Methods Peripheral blood was collected from 17 core family members （9 unaffected, 8 affected） in this Mongolian family with non-syndromie oligodontia. Mutation in exons of PAX9 gene was identified by PCR amplification and DNA sequencing. Results A point mutation c. 87G 〉 C at position 87 in exon 4 of PAX9 was identified from 8 affected members in the family,which were G/C heterozygous. While the 9 healthy members in the family were homozygous for C which was consistent with normal reference sequence in the GenBank （accession number： NC_000014）. Conclusions The mutation of e. 87G 〉 C（p. Ala240Pro） in exon 4 of PAX9 was likely to cause the non-syndromic oligodontia in this Mongolian family.