Gene polymorphisms and elite athletic performance.

Endurance and power performance capacities show much interindividual variation, even among well trained athletes. In the past few years the research was focus on the analysis of the relationship between physiology, biochemistry and genetics in the field of physical exercise, investigating on the inheritance of some traits of performance, on the genetic and molecular basis of training adaptation and on the different indicators of performance.Recently, several studies have shown evidence of the important role of gene polymorphisms in athletic performance. Genetic analysis can be considered a crucial predictive factor only when the gene under scrutiny has a strong influence in a specific physiological pathway or when physiological tests are weakly predictive of adult performance. It is noteworthy that genetic association studies must always be interpreted with caution, for several reasons. It is necessary to verify if the association is attributable to chance or is a false positive result. The association between gene and performance phenotype could even be a consequence of a lack of homogeneity in the genetic substrate of the samples under scrutiny, which could be from different ethnic groups. The number of genes potentially correlated with sport performance is increasing steadily: today it includes 165 autosomal genes and five on the X chromosome. Moreover, there are 17 mitochondrial DNA (mtDNA) genes in which sequence variants influence both fitness and performance phenotypes. Here we review some of the most studied genes on autosomes and in mtDNA that are correlated with potential performance or fitness phenotypes.