The ACTN3 R577X polymorphism in Russian endurance athletes

Area of Science:

• Sports science and genetics
• Human performance and genetic variation
• Exercise physiology

Background:

• The ACTN3 gene encodes alpha-actinin-3, a protein crucial for muscle function.
• The 577R allele is linked to power athletes, while the 577XX genotype (alpha-actinin-3 deficiency) is hypothesized to benefit endurance athletes.
• Understanding ACTN3 genotype distribution is vital for comprehending genetic predispositions in athletic performance.

Purpose of the Study:

• To investigate the distribution of ACTN3 genotypes and alleles in Russian endurance athletes.
• To determine the association between ACTN3 genotypes and competitive results in rowers.
• To clarify the role of ACTN3 in endurance versus power athletic phenotypes.

Main Methods:

• Genotyping of the ACTN3 R577X variant in 456 Russian endurance athletes and 1211 controls.
• Comparison of genotype and allele frequencies between athletes and controls.
• Analysis of rowing performance data from 54 athletes in relation to their ACTN3 genotype.

Main Results:

• The ACTN3 577XX genotype and 577X allele were significantly less frequent in endurance athletes compared to controls (p<0.0001 and p=0.0025, respectively).
• No highly elite endurance athletes possessed the 577XX genotype.
• Male rowers with the 577RR genotype achieved better long-distance rowing times than those with 577RX or 577XX genotypes (p=0.016).

Conclusions:

• The ACTN3 577X allele is under-represented in Russian endurance athletes.
• ACTN3 genotype is associated with competitive performance in rowers.
• The findings suggest a potential disadvantage of the 577X allele in elite endurance performance.