The ACTN3 R577X polymorphism in Russian endurance athletes

Abstract

Objective: The functional 577R allele of the α-actinin-3 (ACTN3) gene has been reported to be associated with elite power athlete status, while the nonfunctional 577XX genotype (predicts an α-actinin-3 deficient phenotype) has been hypothesized as providing some sort of advantage for endurance athletes. In the present study we examined the distribution of ACTN3 genotypes and alleles in Russian endurance-oriented athletes and looked for association between ACTN3 genotypes and the competition results of rowers.

Methods: The study involved 456 Russian endurance-oriented athletes of regional or national competitive standard. ACTN3 genotype and allele frequencies were compared to 1,211 controls. The data from the Russian Cup Rowing Tournament were used to search for possible association between the ACTN3 genotype and the long-distance (~~ 6 km) rowing results of 54 athletes. DNA was extracted from mouthwash samples. Genotyping for the R577X variant was performed by PCR and restriction enzyme digestion.

Results: The frequencies of the ACTN3 577XX genotype (5.7% vs. 14.5%; P < 0.0001) and 577X allele (33.2% vs. 39.0%; P = 0.0025) were significantly lower in endurance-oriented athletes compared to the controls, and none of the highly elite athletes had the 577XX genotype. Furthermore, male rowers with ACTN3 577RR genotype showed better results (1339 ± 11 s) in long-distance rowing than carriers of 577RX (1386 ± 12 s) or 577XX (1402 ± 10 s) genotypes (P=0.016).

Conclusion: Our data show that the ACTN3 577X allele is underrepresented in Russian endurance athletes and is associated with the rowers’ competition results.