ENDOTHELIAL NITRIC OXIDE SYNTHASE GENE POLYMORPHISMS AND ELITE ENDURANCE ATHLETE STATUS

In the GenAthlete case-control study, we examined the contribution of three polymorphisms in the gene coding for the endothelial nitric oxide synthase (NOS3). The hypothesis was that because of its role in the synthesis of NO and influence on endothelial functions, NOS3 could be helpful in discriminating between elite endurance athletes (EEA) and sedentary controls (SC). The EEA group included a total of 216 Caucasian males recruited on the basis that they had a VO2max > 75ml/kg/min. The SC group comprised 214 unrelated sedentary males who had VO2max values below 50ml/kg/min. Subjects in both groups were matched by country of origin. PCR technique was used to amplify a microsatellite (Ca)n repeat containing region in intron 13, a second fragment in intron 4, which includes a 27bp repeat and a third fragment in exon 7 containing the Glu298Asp polymorphism. No difference between EEA and SC group was found for the 27bp repeat and the Glu298Asp polymorphism. Chi-square analysis for the overall allelic distribution of the (CA)n repeat revealed no significant difference between the two groups (p = 0,101). When comparing carriers and non-carriers for the various (CA)n repeat alleles, we found significant differences between SC and EEA, with more EEA subjects carrying the 164bp allele. In summary we found weak evidence to the effect that the 164bp allele of the dinucleotide repeat in intron 13 of the NOS3 gene is observed more frequently in elite endurance athletes than in sedentary controls.