Liu Xing-yuan, Yang Yi-qing, Yang Ying, Lin Xiao-ping, Chen Yi-han
Department of Pediatrics, Tongji University Affiliated Tongji Hospital, Shanghai 200065, China.
Zhonghua Yi Xue Za Zhi. 2009 Sep 15;89(34):2395-9.
To identify the novel genetic defects in patients with congenital ventricular septal defect (VSD).
The clinical data and blood samples from 160 unrelated subjects with congenital VSD were collected and evaluated in comparison with 200 healthy individuals. The coding exons and flanking introns of NKX2-5 gene were amplified by polymerase chain reaction and sequenced using the di-deoxynucleotide chain termination approach. The acquired sequences were aligned with those publicized in GenBank by the aid of program BLAST to identify the sequence variations. The software Clustal W was applied to analyzing the conservation of altered amino acids.
Two novel heterozygous missense NKX2-5 mutations were identified in 3 of 160 VSD patients. The same triplet substitution of TTC for TCC at codon 179, predicting the conversion of serine into phenylalanine at amino acid residue 179 (Ser179Phe), was detected in two cases. Another transition of CGC into AGC at codon 36, leading to the change of arginine into serine at amino acid residue 36 (Arg36Ser), was detected in a third case. These two mutations were not observed in 200 healthy controls. A cross-species alignment of NKX2-5 encoded protein sequences displayed that the mutated amino acids were highly conserved evolutionarily. Additionally, two single nucleotide polymorphisms including a common c. 63A > G and a rare c. 606G > C were observed. However, the polymorphic frequency distributions in VSD cases were not statistically different from those in healthy controls (c. 63A > G: chi(2) = 3.403, P = 0.0651; c. 606G > C: chi(2) = 3.278, P = 0.0702).
Novel NKX2-5 mutations are identified in patients with ASD. They may provide new insight into the molecular etiology responsible for VSD.
鉴定先天性室间隔缺损（VSD）患者的新型基因缺陷。
收集160例先天性VSD无关受试者的临床资料和血样，并与200名健康个体进行比较评估。采用聚合酶链反应扩增NKX2-5基因的编码外显子和侧翼内含子，并使用双脱氧核苷酸链终止法进行测序。借助BLAST程序将获得的序列与GenBank中公布的序列进行比对，以鉴定序列变异。应用Clustal W软件分析氨基酸改变的保守性。
在160例VSD患者中的3例中鉴定出两个新型杂合错义NKX2-5突变。在两例患者中检测到密码子179处TTC三联体替代TCC，预测氨基酸残基179处丝氨酸转变为苯丙氨酸（Ser179Phe）。在第三例患者中检测到密码子36处CGC转变为AGC，导致氨基酸残基36处精氨酸转变为丝氨酸（Arg36Ser）。在200名健康对照中未观察到这两个突变。NKX2-5编码蛋白序列的跨物种比对显示，突变的氨基酸在进化上高度保守。此外，观察到两个单核苷酸多态性，包括一个常见的c.63A>G和一个罕见的c.606G>C。然而，VSD病例中的多态性频率分布与健康对照中的多态性频率分布在统计学上没有差异（c.63A>G：χ2=3.403，P=0.0651；c.606G>C：χ2=3.278，P=0.0702）。
在ASD患者中鉴定出新型NKX2-5突变。它们可能为VSD的分子病因提供新的见解。
