遗传性牙本质发育不全Ⅱ型牙本质涎磷蛋白基因多态性分析

Nucleotide Polymorphism Analysis on the DSPP Gene Causing Dentinogenesis Imperfecta TypeⅡ

目的分析遗传性牙本质发育不全(DGI)Ⅱ型患者DSPP基因突变特征,从分子水平探讨DGI-Ⅱ的发病机制。方法利用FTA洗脱卡对2个遗传性牙本质发育不全Ⅱ型家系成员进行末梢采血,提取纯化基因组DNA;设计引物扩增DSPP基因的5个外显子及其相邻区域,扩增产物鉴定后测序和序列比对分析。结果两个家系的基因检测结果与人类DSPP基因序列比对存在3个碱基替换:外显子4的c.847G>A(p.D243N)是中性突变,外显子4的c.1017A>G(p.S299S)突变和外显子5的c.2091C>T(p.G657G)是同义突变。结论以上三个碱基置换均表现为单核苷酸多态性,其可能为DGI-Ⅱ致病基因的克隆鉴定、实施精准医疗提供参考。

Objective To analyze the characteristics of DSPP gene mutation in patients with dentinogenesis imperfecta type(DGI)Ⅱand explore the pathogenesis of DGI-Ⅱat the molecular level.Methods Peripheral blood samples were collected by FTA elute cards from two families with DGI-Ⅱ,and genomic DNA was extracted from samples.All five DSPP exons were amplified by using primers that flanked the exon-intron boundaries,and the amplified products were identified,sequenced and aligned.Results Sequencing and alignment of DSPP gene showed that three base substitutions in two families with DGI-Ⅱ:the first base substitution for c.847G>A(p.D243N)in exon 4 was neutral mutation,and the other two base substitutions for c.1017A>G(p.S299S)in exon 4 and c.2091C>T(p.G657G)in exon 5 were synonymous mutations.Conclusion The above three base substitutions are all single nucleotide polymorphisms,which may provide reference for the cloning and identification of DGI-Ⅱpathogenic genes and the implementation of precision medicine.