A polymorphism in the alpha2a-adrenoceptor gene and endurance athlete status

WOLFARTH, B., M. A. RIVERA, J-M. OPPERT, M. R. BOULAY, F. T. DIONNE, M. CHAGNON, J. GAGNON, Y. CHAGNON, L. PÉRUSSE, J. KEUL, and C. BOUCHARD. A polymorphism in the alpha2a-adrenoceptor gene and endurance athlete status. Med. Sci. Sports Exerc., Vol. 32, No. 10, pp. 1709–1712, 2000. Purpose In a case control study, we examined the allelic frequencies and genotype distributions of two restricted fragment length polymorphisms (RFLP) in the alpha-2A-adrenoceptor gene (ADRA2A) and beta-2-adrenoceptor gene (ADRB2) among elite endurance athletes (EEA) and sedentary controls (SC). Methods The EEA group included 148 Caucasian male subjects recruited on the basis that they had a V̇O2max > 74 mL O2·kg−1·min−1. The SC group comprised 149 unrelated sedentary male subjects, all Caucasians, from the Quebec Family Study. After digestion with the restriction enzymes Dra I (ADRA2A) and Ban I (ADRB2), Southern blotting and hybridization techniques were used to detect the mutations in the two ADR genes, which are encoded on chromosomes 10 (q24–26) and 5 (q31–32), respectively. Results For the Dra I ADRA2A RFLP, we observed a significant difference in genotype distributions between the two groups (P = 0.037). A higher frequency of the 6.7-kb allele was observed in the EEA group compared with the SC group (P = 0.013). No statistically significant difference was found between groups for the Ban I ADRB2 polymorphic site. Genotype frequencies for both genes in both groups were in Hardy-Weinberg equilibrium. Conclusions In summary, we found evidence that ADRA2A gene variability detected with Dra I is weakly associated with elite endurance athlete status, and we conclude that genetic variation in the ADRA2A gene or a locus in close proximity may play a role in being able to sustain the endurance training regimen necessary to attain a high level of maximal aerobic power.