目的识别法洛四联症(TOF)相关GATA6基因新突变。方法收集2007年1月至2011年10月在上海同济医院连续就诊的120例汉族TOF患者(男63例,女57例,年龄0.5~8.0岁)和200名种族匹配的健康对照者的临床资料和血标本,应用PCR扩增GATA6基因的全部编码外显子及其两侧的部分内含子,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。借助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,利用ClustalW软件分析突变氨基酸的保守性并用MutationTaster软件预测突变的致病性。结果在其中3例TOF患者的GATA6基因各识别出1个新的杂合错义突变,即第73、364和591位的密码子分别由CCC、AGC和GCC变为CTC、CGC和GGC,导致第73、364和591位的氨基酸分别由脯氨酸、丝氨酸和丙氨酸变为亮氨酸、精氨酸和甘氨酸,亦即P.P73L、P.S364R和P.A591G突变。这3种突变均不存在于200名正常对照者中,多物种GATA6序列比对显示突变氨基酸在进化上高度保守,致病性预测显示这3种变异均为致病性突变。结论识别出TOF相关GATA6基因新突变,有助于TOF的早期防治。
Objective To identify the novel mutations in the GATA6 gene associated with tetralogy of Fallot (TOF). Methods The clinical data and blood samples from 120 unrelated Han Chinese TOF patients and 200 unrelated ethnically matched healthy controls were collected. The coding exons and flanking splice junctions of GATA6 gene were amplified by polymerase chain reaction and sequenced by the technique of di-deoxynucleotide chain termination. The acquired sequences were aligned with those derived from GenBank by the aid of program BLAST to identify the sequence variations. The software ClustalW was applied for the conservation analysis of altered amino acids. The pathogenic probability for each sequence variation was predicted automatically by software MutationTaster. Results Three novel heterozygous missense GATA6 mutations were identified in 3 TOF patients. Specifically, the triplet substitutions of CTC for CCC at codon 73, CGC for AGC at eodon 364 and GGC for GCC at codon 591, predicting the transitions of proline into leucine at amino acid residue 73 ( p. P73L) , serine into arginine at amino acid residue 364 (p. $364R) and alanine into glycine at amino acid residue 591 (p. A591G) , were detected. None of three mutations was observed in 200 healthy controls. A cross-species alignment of GATA6 encoded protein sequences showed that the mutated amino acids were highly conserved evolutionarily and all 3 mutations were predicted to be pathogenic. Conclusions Novel mutations are identified in the GATA6 gene associated with TOF. Such a finding may contribute to an early prophylaxis and therapy of TOF.