title: Genetic analysis of essential cardiac transcription factors in 256 patients with non-syndromic congenital heart defects.
abstract: BACKGROUND
  The genetic basis of most congenital heart defects (CHDs), especially non-syndromic and non-familial conditions, remains largely unknown.
  
  
  RESULTS
  DNA samples were collected from immortalized cell lines and original genomes of 256 non-syndromic, non-familial patients with cardiac outflow tract (OFT) defects. Genes encoding NKX2.5, GATA4, GATA6, MEF2C, and ISL1, essential for heart development, were analyzed using PCR-based bidirectional sequencing. The transcriptional activity of proteins with identified sequence variations was analyzed using a luciferase assay. A novel sequence variant (A103V in MEF2C) was identified, in addition to 4 unreported non-synonymous sequence variants in 3 known causative genes (A6V in NKX2.5, T330R and S339R in GATA4, and E142K in GATA6) in 5 individuals. None of these was found in 500 controls without CHDs. In vitro functional assay showed that all proteins with identified sequence variations exhibited significant changes in transcriptional activity and/or synergistic activity with other transcription factors. Furthermore, overexpression of the A103V MEF2C variant in a fish system disturbed early cardiac development.
  
  
  CONCLUSIONS
  New mutations in the transcription factors NKX2.5, GATA4, GATA6, and MEF2C that affect their protein function were identified in 2.3% (6/256) of patients with OFT defects. Our results provide the first demonstration of MEF2C mutation and suggest that disturbances in the regulatory circuits involving these cardiac transcription factors may cause a subset of non-syndromic and non-familial CHDs.
authors.affiliation: Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Kodo
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Nishizawa
authors.forename: Michiko
authors.initials: M
authors.lastname: Furutani
authors.forename: Shoichi
authors.initials: S
authors.lastname: Arai
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Ishihara
authors.forename: Mayumi
authors.initials: M
authors.lastname: Oda
authors.forename: Shinji
authors.initials: S
authors.lastname: Makino
authors.forename: Keiichi
authors.initials: K
authors.lastname: Fukuda
authors.forename: Takao
authors.initials: T
authors.lastname: Takahashi
authors.forename: Rumiko
authors.initials: R
authors.lastname: Matsuoka
authors.forename: Toshio
authors.initials: T
authors.lastname: Nakanishi
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Yamagishi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D016022:Case-Control Studies; D002522:Chlorocebus aethiops; D004252:DNA Mutational Analysis; D050991:GATA4 Transcription Factor / Q000235:genetics; D050993:GATA6 Transcription Factor / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D017930:Genes, Reporter; D020022:Genetic Predisposition to Disease; D006367:HeLa Cells; D006321:Heart / Q000196:embryology; D006330:Heart Defects, Congenital / Q000196:embryology / Q000235:genetics* / Q000378:metabolism; D000072576:Homeobox Protein Nkx-2.5; D018398:Homeodomain Proteins / Q000235:genetics; D006801:Humans; D007564:Japan; D026161:MADS Domain Proteins / Q000235:genetics; D064326:MEF2 Transcription Factors; D008969:Molecular Sequence Data; D009154:Mutation; D009206:Myocardium / Q000378:metabolism*; D018006:Myogenic Regulatory Factors / Q000235:genetics; D009990:Oryzias; D010641:Phenotype; D016133:Polymerase Chain Reaction; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D014162:Transfection
chemical_list: D050991:GATA4 Transcription Factor; C484170:GATA4 protein, human; D050993:GATA6 Transcription Factor; C494759:GATA6 protein, human; D000072576:Homeobox Protein Nkx-2.5; D018398:Homeodomain Proteins; D026161:MADS Domain Proteins; D064326:MEF2 Transcription Factors; C578040:MEF2C protein, human; D018006:Myogenic Regulatory Factors; C095552:NKX2-5 protein, human; D014157:Transcription Factors