NRF2 intron 3 A/G polymorphism is associated with endurance athletes' status.

The aim of this study was to determine the frequency distribution of nuclear respiratory factor 2 (NRF2) intron 3 A/G polymorphism (rs7181866) among 155 Israeli athletes (endurance athletes and sprinters) and 240 healthy controls. Results showed that there was a significantly higher proportion of the AG genotype, rather than the AA genotype, in the group of endurance athletes compared with the sprinters (P = 0.014) and controls (P = 0.0008). However, the sprinters' genotype and allele frequencies were similar to those of the control group (P = 0.62 for genotype distribution percentage). These results were even more pronounced when we compared between the subgroups of 20 elite endurance athletes (those who had represented Israel in a world track-and-field championship or in the Olympic Games) and 54 national-level endurance athletes. In the group of elite endurance athletes the G allele was more frequent than in the national-level endurance athletes (P = 0.047). We conclude that 1) in Israeli athletes the NRF2 AG genotype is more frequent in elite endurance athletes than in sprinters, and 2) within the endurance group the NRF2 AG genotype and the G allele are more frequent in elite athletes, suggesting a positive association between the AG genotype, and possibly the G allele, and the likelihood of being an elite endurance athlete.