title: Polymorphisms in the IGF1 signalling pathway including the myostatin gene are associated with left ventricular mass in male athletes.
abstract: BACKGROUND
  Athlete's heart as an adaptation to long-time and intensive endurance training can vary considerably between individuals. Genetic polymorphisms in the cardiological relevant insulin-like growth factor 1 (IGF1) signalling pathway seem to have an essential influence on the extent of physiological hypertrophy.
  
  
  OBJECTIVE
  Analysis of polymorphisms in the genes of IGF1, IGF1 receptor (IGF1R) and the negative regulator of the cardiac IGF1 signalling pathway, myostatin (MSTN), and their relation to left ventricular mass (LVM) of endurance athletes.
  
  
  METHODS
  In 110 elite endurance athletes or athletes with a high amount of endurance training (75 males and 35 females) and 27 male controls, which were examined by echocardiographic imaging methods and ergometric exercise-testing, the genotypes of a cytosine-adenine repeat polymorphism in the promoter region of the IGF1 gene and a G/A substitution at position 3174 in the IGF1R gene were determined. Additionally, a mutation screen of the MSTN gene was performed.
  
  
  RESULTS
  The polymorphisms in the IGF1 and the IGF1R gene showed a significant relation to the LVM for male (IGF1: p=0.003; IGF1R: p=0.01), but not for female athletes. The same applies to a previously unnoticed polymorphism in the 1 intron of the MSTN gene, whose deletion allele (AAA→AA) appears to increase the myostatic effect (p=0.015). Moreover, combinations of the polymorphisms showed significant synergistic effects on the LVM of the male athletes.
  
  
  CONCLUSIONS
  The authors' results argue for the importance of polymorphisms in the IGF1 signalling pathway in combination with MSTN on the variant degree of physiological hypertrophy of male athletes.
authors.affiliation: Institute of Human Genetics, University of Saarland/IGD Saar GmbH, Homburg/Saar, Germany.
authors.forename: Ruth-Jessica
authors.initials: RJ
authors.lastname: Karlowatz
authors.forename: Jürgen
authors.initials: J
authors.lastname: Scharhag
authors.forename: Jörg
authors.initials: J
authors.lastname: Rahnenführer
authors.forename: Ulrich
authors.initials: U
authors.lastname: Schneider
authors.forename: Ernst
authors.initials: E
authors.lastname: Jakob
authors.forename: Wilfried
authors.initials: W
authors.lastname: Kindermann
authors.forename: Klaus Dieter
authors.initials: KD
authors.lastname: Zang
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D004452:Echocardiography; D005260:Female; D005838:Genotype; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000000981:diagnostic imaging / Q000235:genetics*; D007334:Insulin-Like Growth Factor I / Q000235:genetics*; D008297:Male; D055435:Myostatin / Q000235:genetics*; D017354:Point Mutation / Q000235:genetics; D011110:Polymorphism, Genetic / Q000235:genetics*; D017526:Receptor, IGF Type 1 / Q000235:genetics*; D013177:Sports; D055815:Young Adult
chemical_list: D055435:Myostatin; D007334:Insulin-Like Growth Factor I; D017526:Receptor, IGF Type 1