title: Missense mutations in desmocollin-2 N-terminus, associated with arrhythmogenic right ventricular cardiomyopathy, affect intracellular localization of desmocollin-2 in vitro.
abstract: BACKGROUND
  Mutations in genes encoding desmosomal proteins have been reported to cause arrhythmogenic right ventricular cardiomyopathy (ARVC), an autosomal dominant disease characterised by progressive myocardial atrophy with fibro-fatty replacement. We screened 54 ARVC probands for mutations in desmocollin-2 (DSC2), the only desmocollin isoform expressed in cardiac tissue.
  
  
  METHODS
  Mutation screening was performed by denaturing high-performance liquid chromatography and direct sequencing. To evaluate the pathogenic potentials of the DSC2 mutations detected in patients affected with ARVC, full-length wild-type and mutated cDNAs were cloned in eukaryotic expression vectors to obtain a fusion protein with green fluorescence protein (GFP); constructs were transfected in neonatal rat cardiomyocytes and in HL-1 cells.
  
  
  RESULTS
  We identified two heterozygous mutations (c.304G>A (p.E102K) and c.1034T>C (p.I345T)) in two probands and in four family members. The two mutations p.E102K and p.I345T map to the N-terminal region, relevant to adhesive interactions. In vitro functional studies demonstrated that, unlike wild-type DSC2, the two N-terminal mutants are predominantly localised in the cytoplasm.
  
  
  CONCLUSIONS
  The two missense mutations in the N-terminal domain affect the normal localisation of DSC2, thus suggesting the potential pathogenic effect of the reported mutations. Identification of additional DSC2 mutations associated with ARVC may result in increased diagnostic accuracy with implications for genetic counseling.
authors.affiliation: Department of Biology, University of Padua, Padua, Italy. giorgia.beffagna@unipd.it
authors.forename: Giorgia
authors.initials: G
authors.lastname: Beffagna
authors.forename: Marzia
authors.initials: M
authors.lastname: De Bortoli
authors.forename: Andrea
authors.initials: A
authors.lastname: Nava
authors.forename: Michela
authors.initials: M
authors.lastname: Salamon
authors.forename: Alessandra
authors.initials: A
authors.lastname: Lorenzon
authors.forename: Manuela
authors.initials: M
authors.lastname: Zaccolo
authors.forename: Luisa
authors.initials: L
authors.lastname: Mancuso
authors.forename: Luca
authors.initials: L
authors.lastname: Sigalotti
authors.forename: Barbara
authors.initials: B
authors.lastname: Bauce
authors.forename: Gianluca
authors.initials: G
authors.lastname: Occhi
authors.forename: Cristina
authors.initials: C
authors.lastname: Basso
authors.forename: Gerolamo
authors.initials: G
authors.lastname: Lanfranchi
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Towbin
authors.forename: Gaetano
authors.initials: G
authors.lastname: Thiene
authors.forename: Gian Antonio
authors.initials: GA
authors.lastname: Danieli
authors.forename: Alessandra
authors.initials: A
authors.lastname: Rampazzo
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D019571:Arrhythmogenic Right Ventricular Dysplasia / Q000235:genetics*; D002478:Cells, Cultured; D051187:Desmocollins / Q000235:genetics*; D005260:Female; D006580:Genetic Carrier Screening; D049452:Green Fluorescent Proteins; D006801:Humans; D008297:Male; D008875:Middle Aged; D020125:Mutation, Missense; D032383:Myocytes, Cardiac; D051381:Rats; D014162:Transfection
chemical_list: C081561:DSC2 protein, human; D051187:Desmocollins; D049452:Green Fluorescent Proteins