Increased prevalence of the null allele of the p.Arg577Ter variant in the ACTN3 gene in Brazilian long‐distance athletes: A retrospective study

Abstract

IntroductionThe phenotypic consequences of the p.Arg577Ter variant in the α‐actinin‐3 (ACTN3) gene are suggestive of a trade‐off between performance traits for speed and endurance sports. Although there is a consistent association of the c.1729C allele (aka R allele) with strength/power traits, there is still a debate on whether the null allele (c.1729T allele; aka X allele) influences endurance performance. The present study aimed to test the association of the ACTN3 p.Arg577Ter variant with long‐distance endurance athlete status, using previously published data with the Brazilian population.MethodsGenotypic data from 203 long‐distance athletes and 1724 controls were analysed in a case–control approach.ResultsThe frequency of the X allele was significantly higher in long‐distance athletes than in the control group (51.5% vs. 41.4%; p = 0.000095). The R/X and X/X genotypes were overrepresented in the athlete group. Individuals with the R/X genotype instead of the R/R genotype had a 1.6 increase in the odds of being a long‐distance athlete (p = 0.012), whereas individuals with the X/X genotype instead of the R/R genotype had a 2.2 increase in the odds of being a long‐distance athlete (p = 0.00017).ConclusionThe X allele, mainly the X/X genotype, was associated with long‐distance athlete status in Brazilians.