多数牙先天缺失可能与MSX1上的3个SNPs相关

The detection of MSX1 gene mutations in patients with oligodontia

目的:探讨多数牙先天缺失患者的MSX1基因突变位点。方法:从4个多数牙先天缺失患者与家庭部分成员、1个唇腭裂并发少数牙先天缺失的患者、1个牙列完整的对照儿童共14人的静脉血中提取DNA,在MSX1基因内设计引物,采用PCR方法扩增MSX1基因外显子1、2的编码区,而后对外显子1、2的PCR纯化产物测序,结合系谱进行序列比对分析。结果:发现3个可能的单核苷酸多态性位点(single nucleotide pol-ymorphisms,SNPs)。这3个SNPs均位于外显子1中,且来自不同家系的3个患者在这3个位点上同时出现杂合突变。其中,311位点由G变A,对应的密码子由编码甘氨酸的GGC变为编码天门冬氨酸的GAC,发生了错义突变;402位点由C变A,对应的密码子由CCC变为CCA,但仍编码脯氨酸,属同义突变;458位点由C变T,对应的密码子由编码丙氨酸的GCC变为编码缬氨酸的GTC,发生了错义突变。结论:多数牙先天缺失可能与MSX1基因上该3个单核苷酸多态性位点有关。

Objective： To detect the mutation sites of MSX1 that contributes to the oligodontia in humans. Methods： 4 individuals with oligodontia, and their family members, I individual with oligodontia complicated by eheilopalatognathus were consisted. The control group consisted of 1 normal individual. DNA was extracted from all 14 individuals＇venous blood. The primer was designed within MSX1 gene. The polymerase chain reaction （PCR） for the coding region of exon 1 and 2 was carried out. The purified PCR products was sequeced and analysed with pedigree. Results： 3 single nucleotide polymorphisms（SNPs） in exon 1 have been detected, which were obtained from 3 oligodontia patients and 1 patient with oligodontia complicated by eheilopalatognathus. Among them, the 311 th site in exon 1 changes from G to A, and corresponding codon changes from encoding glycine GGC to encoding Asp GAC that is a missense mutation. The 402th site in exon 1 changes from C to A, corresponding codon changes from CCC to CCA, But it encodes proline still, which is a same-sense mutation. The 458th site in exon 1 changes from C to T, corresponding codon changes from GCC encoding alanine to GTC encoding valine that is a missense mutation. Conclusion： The 3 SNPs in MSX1 probably contribute to oligodontia in humans.