Abstract for presentation at 11th International Congress of Human Genetics

Rapid genotyping of R577X and Q523R polymorphisms of Actinin alpha 3 gene, in the Italian population and elite endurance athletes by real time pcr

  • Andrea Paparini, Department of Health Sciences - IUSM, Italy
  • Daniele Santoni, Department of Health Sciences - IUSM, Italy
  • Giuseppe Giordano Drago, Department of Health Sciences - IUSM, Italy
  • Gianluca Gianfranceschi, Department of Health Sciences - IUSM, Italy
  • Antonio Spataro, Department of Health Sciences - IUSM, Italy
  • Fabio Pigozzi, Department of Health Sciences - IUSM, Italy
  • Maurizio Ripani, Department of Health Sciences - IUSM, Italy
  • Vincenzo Romano Spica, Department of Health Sciences - IUSM, Italy

    • Athletic performance is a multifactorial polygenic trait influenced by training, environment and genetic predisposition. The human gene map for performance and health-related fitness phenotypes includes over 140 gene entries and QTL, plus 16 mitochondrial genes. Alpha actinins are a family of highly conserved sarcomeric actin-binding proteins, related to distrophin. ACTN mammalian isoforms are classified as non-muscle cytoskeletal or muscle sarcomeric, and are differentially expressed. Congenital deficiency of ACTN3 involves about 16% of the world population, and seems not associated with human disease. It is caused by a premature stop codon in ACTN3 gene (11q13-14) in position 1,747 on exon 16 (R577X). Evidences suggest a role for ACTN3 polymorphisms in sport performance. An additional SNP (Q523R) has been described in linkage disequilibrium with 577X. A TaqMan real-time PCR procedure to simultaneously type R577X and Q523R polymorphisms was established and applied to DNA samples from the general Italian population (n= 102) and elite male endurance athletes (n=27). Amplification products were confirmed by RFLP-PCR. The R577X genotype distribution in the general population was: 22% XX, 47% RX, 31% RR. In the cohort of athletes the percentage of XX homozygous subjects was 22%, heterozygotes and RR homozygotes were 56% and 22%, respectively. The Q523R genotype distribution was: 23% RR, 47% RQ, 30% QQ; in the athletes: 19% RR, 59% RQ, QQ 22%. No significant differences were detected in allelic distribution in the athlete sample with respect to the general population. A highly significant (p<0.001) linkage disequilibrium between Q523R and R577X in the Italian general population and athletes samples was confirmed. Haplotype distributions respected the H-W equilibrium (p>0.3). Analysis of genetic polymorphisms at sarcomeric proteins may open up promising perspectives to understand muscular rehabilitation processes and genetic predisposition in sport excellence.

    ACTN3 POLYMORPHISMS IN ITALIAN POPULATION AND IN ENDURANCE ATHLETES
    Allele frequency: Q523R Allele frequency: R577X
    Q R R X
    GENERAL POPULATION 0.54 0.46 0.55 0.45
    ATHLETES 0.52 0.48 0.50 0.50
    Conference Organiser - ICMS Pty Ltd