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目的了解MEF2C基因在新疆维吾尔族儿童单纯性先天性心脏病患者人群中的突变情况,探讨其与该疾病的相关性,为进一步阐明先天性心脏病发病的分子机理提供新的实验依据。方法收集200例无血缘关系的单纯性先天性心脏病儿童患者的临床资料以及血液标本,同时随机选取200例无血缘关系的健康儿童做对照。提取外周血DNA,应用聚合酶链反应扩增MEF2C基因的全部编码外显子,用直接测序法对所扩增出来的片段进行测序,分析测序结果并用blast程序将所测序列与GenBank中已知的序列进行比对,识别出基因突变,并用序列比对软件ClustalW分析突变氨基酸的保守性。结果在3例无血缘关系的维吾尔族先天性心脏病患者中发现新的突变,其中1个是MEF2C基因编码核苷酸序列第803位的A变为G即c.803A>G突变;另一个是第809位的G变为A,即c.809G>A突变,最后一个是第856位的A变为C,即c.856A>C突变,在另外3例中发现新的插入,其中一个是MEF2C基因编码核苷酸序列第134位插入了一个A,另一个是第812位插入了一个A;最后一个是第836位插入了一个A。这些突变不存在于正常对照组,多序列比对显示6种突变氨基酸在进化上均高度保守。结论此次研究发现与先天性心脏病可能相关的新突变,有助于揭示先天性心脏病新的分子病因。
Objective To investigate the mutation of MEF2C gene in the population of simple Uygur children with congenital heart disease in Xinjiang and to explore the relationship between the MEF2C gene and the disease so as to provide new experimental evidence for further elucidating the molecular mechanism of congenital heart disease. Methods The clinical data and blood samples of 200 children with unrelated simple congenital heart disease were collected. At the same time, 200 unrelated and healthy children were randomly selected as control. The DNA of peripheral blood was extracted and all the exons encoding MEF2C gene were amplified by polymerase chain reaction (PCR). The amplified fragments were sequenced by direct sequencing. The sequencing results were analyzed and compared with known sequences in GenBank The mutations were identified and the amino acid conservation of the mutant amino acids was analyzed using the sequence alignment software ClustalW. Results Three new mutations were found in 3 unrelated patients with Uygur congenital heart disease. One of them was a mutation of A at position 803 of the MEF2C gene coding sequence, ie, c.803A> G mutation. The other Is the 809th G becomes A, that is, the c.809G> A mutation, the last is the 856th A becomes C, that is, the c.856A> C mutation, and in the other 3 cases a new insertion is found, one of which MEF2C gene encoding nucleotide sequence inserted a 134th, the other is a 818th insert an A; the last one is inserted at the 836th of an a. These mutations do not exist in the normal control group, multiple sequence alignment showed that six kinds of mutant amino acids were highly conserved evolutionarily. Conclusions This study found that new mutations that may be associated with congenital heart disease could help reveal new molecular causes of congenital heart disease.