先天性房间隔缺损相关GATA4基因新突变的筛查

目的 筛查先天性房间隔缺损相关GATA4基因的新突变.方法 收集85例先天性房间隔缺损患者和200名健康者的临床资料及外周静脉血标本.应用聚合酶链反应扩增GATA4基因的全部外显子,采用双脱氧核苷链末端合成终止法对全部扩增片段进行测序.以BLAST程序将所测序列与GenBank中的已知序列进行比对,以识别基因突变.采用Clustal W软件分析突变氨基酸的保守性.结果 在其中3例先天性房间隔缺损患者的GATA4基因各识别出1个新的杂合错义突变,即第267、354和407位的密码子分别由GTG、ACC和CCA变为ATG、GCC和CAA,亦即c.799G>A、c.1060A>G和c.1220C>A突变,相应地导致第267、354和407位的氨基酸分别由缬氨酸、苏氨酸和脯氨酸变为蛋氨酸、丙氨酸和谷氨酰胺,也称为p.V267M、p.T354A和p.P407Q突变.200名健康对照者均无上述突变.多物种GATA4序列比对显示,第267位的缬氨酸和第407位的脯氨酸在进化上完全保守.结论 在先天性房间隔缺损患者的GATA4基因识别出3个新的杂合错义突变,揭示了先天性房间隔缺损新的分子病因,有助于先天性房间隔缺损的早期防治.

Genetic screening for novel GATA4 mutations associated with congenital atrial septal defect

Objective To screen the gene CATA4 for novel mutations associated with congenital atria] septal defect ( ASD). Methods The clinical data and peripheral venous blood specimen from 85 unrelated subjects with congenital ASD were collected and analyzed in contrast to 200 healthy individuals. The coding exons and the exon/intron boundaries of GATA4 gene were amplified by polymerase chain reaction and sequenced using the di-deoxynucleotide chain termination procedure. The obtained sequences were aligned with those publicized in GenBank with the help of programme BLAST to identify the sequence variations. The software Clustal W was applied to analysis of the conservation of altered amino acids. Results Three novel heterozygous missense GATA4 mutations were identified in 3 of 85 ASD patients, respectively. Namely, the triplet substitutions of ATG for GTG at codon 267, GCC for ACC at codon 354, and CAA for CCA at codon 407, predicting the conversions of valine into methionine at amino acid residue 267 ( V267M) , threonine into alanine at amino acid residue 354 (T354A), and proline into glutamine at amino acid residue 407 (P407Q) , were identified. No mutation was detected in 200 healthy controls. A cross-species alignment of GATA4 encoded protein sequences showed that the valine at amino acid residue 267 and proline at amino acid residue 407 were completely conserved evolutionarily. Conclusion Three novel heterozygous missense GATA4 mutations were identified in patients with congenital ASD, which reveals new molecular etiology responsible for ASD, and contributes to the early prophylaxis and therapy for ASD.