The association of the R577X and I/D polymorphisms with athlete status in football: a systematic review and meta-analysis.

The aim of this review was to assess the association of R577X and I/D polymorphisms with athlete status in football and determine which allele and/or genotypes are most likely to influence this phenotype via a meta-analysis. A comprehensive search identified 17 and 19 studies. Significant associations were shown between the presence of the R allele and professional footballer status (OR = 1.35, 95% CI: 1.18-1.53) and the D allele and youth footballers (OR = 1.18, 95% CI: 1.01-1.38). More specifically, the RR genotype (OR = 1.48, 95% CI: 1.23-1.77) and DD genotype (OR = 1.29, 95% CI: 1.02-1.63) exhibited the strongest associations, respectively. These findings may be explained by the association of the RR genotype and DD genotype with power-orientated phenotypes and the relative contribution of power-orientated phenotypes to success in football. As such, the results of this review provide further evidence that individual genetic variation may contribute towards athlete status and can differentiate athletes of different competitive playing statuses in a homogenous team-sport cohort. Moreover, the R577X and I/D polymorphisms are likely (albeit relatively minor) contributing factors that influence athlete status in football.