一例颅锁骨发育不良患儿的RUNX2基因突变研究

A Chinese girl with cleidocranial dysplasia (CCD) caused by recurrent R190W mutation in RUNX 2

目的 报告 1中国人常染色体显性遗传颅锁骨发育不良的临床病例并对其致病基因RUNX 2进行突变鉴定。方法 根据患儿的症状、体征、骨骼系统放射线检查和相关血液生化检查进行临床诊断。提取患儿外周血DNA ,PCR扩增RUNX 2编码氨基酸的 7个外显子片段 ,测序检测突变。结果 患儿 ,女 ,5岁 ,具有前囟大、双锁骨缺失、身材矮小、牙齿异常等典型颅锁骨发育不良临床表现。PCR扩增片段直接测序显示患儿RUNX 2外显子 2内发生R190W (5 6 8C >T)错义突变。该突变通过PCR产物的HaeIII限制酶切分析得到进一步确认。结论 报告一例颅锁骨发育不良病例并发现RUNX 2一复发点突变为其致病的遗传基础。

Objective Cleidocranial dyspl asia (CCD) is a rare skeletal disease with autosomal dominant inheritance associ ated with mutation in RUNX 2. The authors report a Chinese girl with CCD in whom the mutation in RUNX 2 was identified. Methods Clinical diagnosis was based on physical examination, radiological findings, and biochemical tests. For mutation detection, genomic DNA was extracted from p eripheral blood using standard method. All 7 coding exons of RUNX 2 and the ir flanking intronic sequences were amplified by polymerase chain reaction (PCR) , and the PCR products were then subjected to automatic DNA sequencing. Results The affected girl showed typical clinical manifestations of CCD, including patent fontanelles, absent clavicles, short stature and denta l anomalies. Direct sequencing of PCR-amplified fragments revealed a recurrent missense mutation, R190W (568C>T), in RUNX 2. The mutation was further con firmed by Hae III restriction analysis. Conclusion A Chinese case of CCD was confirmed and the disease-causing mutation was linked to a recurrent point mutation in RUNX 2.