两个新RUNX2基因突变引起家族性锁骨颅骨发育不全

目的 探讨RUNX2基因突变在锁骨颅骨发育不全病因研究中的意义及两个中国家族性锁骨颅骨发育不全家系发病的分子机制.方法 提取收集到的2个锁骨颅骨发育不全家系中4例患者和4名家系健康成员、102名无关正常对照外周血基因组DNA,应用PCR扩增产物双向直接测序方法 检测RUNX2基因第1～7外显子及相邻侧翼区的DNA序列,测序结果 与RUNX2基因正常序列对比分析.对发现的突变位点用酶切方法 证实.结果 测序结果 发现一家系中两例父子患者的RUNX2基因第1外显子发生错义突变c.346T＞A(W116R),该错义突变通过Bsr Ⅰ限制性内切酶对PCR扩增产物行酶切分析得到进一步确认.另一家系中两例患者的RUNX2基因第3外显子发生无义突变c.610A＞T(K204X).在两个家系中的正常家系成员和无关正常对照RUNX2基因DNA序列中没有发现上述突变.结论 通过RUNX2基因,检测在中国人群中发现两个RUNX2基因新致病突变,扩展了遗传性锁骨颅骨发育不全的基因突变谱,对阐明该病发病机制及其基因诊断和遗传咨询有重要意义.

Two novel RUNX2 gene mutations in two Chinese families with cleidocranial dysplasia

Objective To identify the RUNX2 gene mutation in two unrelated Chinese families with cleidocranial dysplasia (CCD), and to assess the feasibility of gene diagnosis for patients with CCD. Methods Genomic DNA was isolated from peripheral blood samples of 4 patients and 4 healthy members in the two pedigrees as well as 102 unrelated healthy controls. All 7 coding exons and their flanking intronic sequences of the RUNX2 gene were amplified by PCR, then the PCR products were sequenced bi-directionally. The sequencing results were compared with normal sequences in GenBank to identify the mutation. The mutation was confirmed by RFLP with restriction endonuclease. Results In one family, a novel heterozygous missense mutation c. 346T＞A (W116R) in exon 1 of the RUNX2 gene was detected in the two affected individuals, and the mutation was further confirmed with Bsr Ⅰ restriction endonuclease digestion. In the other family, a novel nonsense mutation c. 610A＞T (K204X) was identified in the two patients. No above sequence change was found in the 102 healthy controls. Conclusion Two novel RUNX2 mutations were found in two unrelated Chinese families with cleidoeranial dysplasia. The identification of these mutations further extended the mutation spectrum of RUNX2 gene and will facilitate prenatal diagnosis and gene diagnosis of CCD.