title: Recurrent and founder mutations in the Netherlands: cardiac Troponin I (TNNI3) gene mutations as a cause of severe forms of hypertrophic and restrictive cardiomyopathy.
abstract: BACKGROUND
  About 2-7% of familial cardiomyopathy cases are caused by a mutation in the gene encoding cardiac troponin I (TNNI3). The related clinical phenotype is usually severe with early onset. Here we report on all currently known mutations in the Dutch population and compared these with those described in literature.
  
  
  METHODS
  TheTNNI3 gene was screened for mutations in all coding exons and flanking intronic sequences in a large cohort of cardiomyopathy patients. All Dutch index cases carrying a TNNI3 mutation that are described in this study underwent extensive cardiological evaluation and were listed by their postal codes.
  
  
  RESULTS
  In 30 families, 14 different mutations were identified. Three TNNI3 mutations were found relatively frequently in both familial and non-familial cases of hypertrophic cardiomyopathy (HCM) or restrictive cardiomyopathy (RCM). Haplotype analysis showed that p.Arg145Trp and p.Ser166Phe are founder mutations in the Netherlands, while p.Glu209Ala is not. The majority of Dutch TNNI3 mutations were associated with a HCM phenotype. Mean age at diagnosis was 36.5 years. Mutations causing RCM occurred less frequently, but were identified in very young children with a poor prognosis.
  
  
  CONCLUSIONS
  In line with previously published data, we found TNNI3 mutations to be rare and associated with early onset and severe clinical presentation.
authors.affiliation: Department of Clinical Genetics, Maastricht University Medical Center, Maastricht, the Netherlands, arthur.vdwijngaard@mumc.nl.
authors.forename: A
authors.initials: A
authors.lastname: van den Wijngaard
authors.forename: P
authors.initials: P
authors.lastname: Volders
authors.forename: J P
authors.initials: JP
authors.lastname: Van Tintelen
authors.forename: J D H
authors.initials: JD
authors.lastname: Jongbloed
authors.forename: M P
authors.initials: MP
authors.lastname: van den Berg
authors.forename: R H
authors.initials: RH
authors.lastname: Lekanne Deprez
authors.forename: M M A M
authors.initials: MM
authors.lastname: Mannens
authors.forename: N
authors.initials: N
authors.lastname: Hofmann
authors.forename: M
authors.initials: M
authors.lastname: Slegtenhorst
authors.forename: D
authors.initials: D
authors.lastname: Dooijes
authors.forename: M
authors.initials: M
authors.lastname: Michels
authors.forename: Y
authors.initials: Y
authors.lastname: Arens
authors.forename: R
authors.initials: R
authors.lastname: Jongbloed
authors.forename: B J M
authors.initials: BJ
authors.lastname: Smeets