title: TBX20 loss-of-function mutation associated with familial dilated cardiomyopathy.
abstract: BACKGROUND
  Dilated cardiomyopathy (DCM) is a major cause of congestive heart failure, sudden cardiac death and cardiac transplantation. Aggregating evidence highlights the genetic origin of DCM. However, DCM is a genetically heterogeneous disorder, and the genetic components underlying DCM in most cases remain unknown.
  
  
  METHODS
  The coding regions and splicing junction sites of the TBX20 gene were sequenced in 120 unrelated patients with idiopathic DCM. The available close relatives of the index patient carrying an identified mutation and 300 unrelated ethnically matched healthy individuals used as controls were genotyped for TBX20. The functional characteristics of the mutant TBX20 were assayed in contrast to its wild-type counterpart by using a dual-luciferase reporter assay system.
  
  
  RESULTS
  A novel heterozygous TBX20 mutation, p.F256I, was identified in a family with DCM transmitted in an autosomal dominant fashion, which co-segregated with DCM in the family with complete penetrance. The missense mutation was absent in 600 control chromosomes and the altered amino acid was completely conserved evolutionarily among various species. Functional assays revealed that the mutant TBX20 had significantly diminished transcriptional activity. Furthermore, the mutation markedly reduced the synergistic activation of TBX20 with NKX2-5 or GATA4.
  
  
  CONCLUSIONS
  This study links TBX20 loss-of-function mutation to idiopathic DCM in humans for the first time, providing novel insight into the molecular mechanism underpinning DCM.
authors.forename: Cui-Mei
authors.initials: CM
authors.lastname: Zhao
authors.lastname: Bing-Sun
authors.forename: Hao-Ming
authors.initials: HM
authors.lastname: Song
authors.forename: Juan
authors.initials: J
authors.lastname: Wang
authors.forename: Wen-Jun
authors.initials: WJ
authors.lastname: Xu
authors.forename: Jin-Fa
authors.initials: JF
authors.lastname: Jiang
authors.forename: Xing-Biao
authors.initials: XB
authors.lastname: Qiu
authors.forename: Fang
authors.initials: F
authors.lastname: Yuan
authors.forename: Jia-Hong
authors.initials: JH
authors.lastname: Xu
authors.forename: Yi-Qing
authors.initials: YQ
authors.lastname: Yang
mesh_terms: D000328:Adult; D000483:Alleles; D000818:Animals; D001483:Base Sequence; D019556:COS Cells; D002311:Cardiomyopathy, Dilated / Q000235:genetics* / Q000473:pathology; D016022:Case-Control Studies; D002522:Chlorocebus aethiops; D005260:Female; D050991:GATA4 Transcription Factor / Q000235:genetics; D017930:Genes, Reporter; D005838:Genotype; D006579:Heterozygote; D000072576:Homeobox Protein Nkx-2.5; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D016297:Mutagenesis, Site-Directed; D020125:Mutation, Missense; D010375:Pedigree; D017422:Sequence Analysis, DNA; D020825:T-Box Domain Proteins / Q000235:genetics* / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D050991:GATA4 Transcription Factor; D000072576:Homeobox Protein Nkx-2.5; D018398:Homeodomain Proteins; C095552:NKX2-5 protein, human; D020825:T-Box Domain Proteins; C420984:TBX20 protein, human; D014157:Transcription Factors