title: Prevalence and spectrum of Nkx2.6 mutations in patients with congenital heart disease.
abstract: Congenital heart disease (CHD) is the most common form of birth defect and is the most prevalent non-infectious cause of infant death. A growing body of evidence documents that genetic defects are involved in the pathogenesis of CHD. However, CHD is a genetically heterogeneous disease and the genetic basis underpinning CHD in an overwhelming majority of patients remain unclear. In this study, the coding exons and flanking introns of the Nkx2.6 gene, which codes for a homeodomain-containing transcription factor important for normal cardiovascular development, were sequenced in 320 unrelated patients with CHD, and two novel heterozygous Nkx2.6 mutations, p.V176M and p.K177X, were identified in two unrelated patients with CHD, respectively, including a patient with tetralogy of Fallot and a patient with double outlet of right ventricle and ventricular septal defect. The mutations were absent in 400 control chromosomes and the altered amino acids were completely conserved evolutionarily across species. Due to unknown transcriptional targets of Nkx2.6, the functional consequences of the identified mutations at transcriptional activity were evaluated by using Nkx2.5 as a surrogate. Alignment between human Nkx2.6 and Nkx2.5 proteins showed that V176M-mutant Nkx2.6 was equivalent to V182M-mutant Nkx2.5 and K177X-mutant Nkx2.6 was equal to K183X-mutant Nkx2.5, and introduction of V182M or K183X into Nkx2.5 significantly diminished its transcriptional activating function when compared with its wild-type counterpart. To our knowledge, this is the first report on the association of Nkx2.6 loss-of-function mutation with increased susceptibility to tetralogy of Fallot or double outlet of right ventricle and ventricular septal defect, providing novel insight into the molecular mechanism of CHD.
authors.affiliation: Department of Cardiology, Yantaishan Hospital, 91 Jiefang Road, Yantai 264001, Shandong, China.
authors.forename: Lan
authors.initials: L
authors.lastname: Zhao
authors.affiliation: Department of Pediatrics, Baoshan Branch of Huashan Hospital, Fudan University, 1999 West Changjiang Road, Shanghai 200431, China.
authors.forename: Shi-Hong
authors.initials: SH
authors.lastname: Ni
authors.affiliation: Department of Pediatrics, Tongji Hospital, Tongji University School of Medicine, 389 Xincun Road, Shanghai 200065, China.
authors.forename: Xing-Yuan
authors.initials: XY
authors.lastname: Liu
authors.affiliation: Department of Neonatology, Shanghai Children's Hospital, Shanghai Jiao Tong University, 1400 West Beijing Road, Shanghai 200040, China.
authors.forename: Dong
authors.initials: D
authors.lastname: Wei
authors.affiliation: Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, 241 West Huaihai Road, Shanghai 200030, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Yuan
authors.affiliation: Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, 241 West Huaihai Road, Shanghai 200030, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Xu
authors.affiliation: Department of Extracorporal Circulation, Shanghai Chest Hospital, Shanghai Jiao Tong University, 241 West Huaihai Road, Shanghai 200030, China.
authors.lastname: Xin-Li
authors.affiliation: Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, 241 West Huaihai Road, Shanghai 200030, China.
authors.forename: Ruo-Gu
authors.initials: RG
authors.lastname: Li
authors.affiliation: Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, 241 West Huaihai Road, Shanghai 200030, China.
authors.forename: Xin-Kai
authors.initials: XK
authors.lastname: Qu
authors.affiliation: Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, 241 West Huaihai Road, Shanghai 200030, China.
authors.forename: Ying-Jia
authors.initials: YJ
authors.lastname: Xu
authors.affiliation: Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, 241 West Huaihai Road, Shanghai 200030, China.
authors.forename: Wei-Yi
authors.initials: WY
authors.lastname: Fang
authors.affiliation: Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, 241 West Huaihai Road, Shanghai 200030, China; Cardiovascular Research Laboratory, Shanghai Chest Hospital, Shanghai Jiao Tong University, 241 West Huaihai Road, Shanghai 200030, China; Central Laboratory, Shanghai Chest Hospital, Shanghai Jiao Tong University, 241 West Huaihai Road, Shanghai 200030, China. Electronic address: qxingbiao@sina.cn.
authors.forename: Yi-Qing
authors.initials: YQ
authors.lastname: Yang
authors.affiliation: Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, 241 West Huaihai Road, Shanghai 200030, China.
authors.forename: Xing-Biao
authors.initials: XB
authors.lastname: Qiu
mesh_terms: D044466:Asian People / Q000235:genetics; D004310:Double Outlet Right Ventricle / Q000235:genetics; D005260:Female; D006330:Heart Defects, Congenital / Q000235:genetics*; D006345:Heart Septal Defects, Ventricular / Q000235:genetics; D000072576:Homeobox Protein Nkx-2.5; D018398:Homeodomain Proteins / Q000235:genetics*; D006801:Humans; D008297:Male; D009154:Mutation; D013771:Tetralogy of Fallot / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics
chemical_list: D000072576:Homeobox Protein Nkx-2.5; D018398:Homeodomain Proteins; D014157:Transcription Factors; C095552:NKX2-5 protein, human; C501915:NKX2-6 protein, human
keywords: Congenital heart disease; Genetics; Nkx2.6; Reporter gene assay; Transcription factor