A polymorphism in the alpha(2a)-adrenoceptor gene and endurance athlete status

Purpose: In a case control study, we examined the allelic frequencies and g enotype distributions of two restricted fragment length polymorphisms (RnP) in the alpha-2A-adrenoceptor gene (ADRA2A) and beta-2-adrenoceptor gene (A DRB2) among elite endurance athletes (EEA) and sedentary controls (SC). Met hods: The EEA group included 148 Caucasian male subjects recruited on the b asis that they had a (V) over dot O-2max > 74 mL O-2.kg(-1).min(-1). The SC group comprised 149 unrelated sedentary male subjects, all Caucasians, fro m the Quebec Family Study. After digestion with the restriction enzymes Dra I (ADRA2A) and Ban I (ADRB2), Southern blotting and hybridization techniqu es were used to detect the mutations in the two ADR genes, which are encode d on chromosomes 10 (q24-26) and 5 (q31-32), respectively. Results: For the Dra I ADRA2A RFLP, we observed a significant difference in genotype distri butions between the two groups (P = 0.037). A higher frequency of the 6.7-k b allele was observed in the EEA group compared with the SC group (P = 0.01 3). No statistically significant difference was found between groups for th e Ban I ADRB2 polymorphic site. Genotype frequencies for both genes in both groups were in Hardy-Weinberg equilibrium. Conclusions: In summary, we fou nd evidence that PLDRA2A gene variability detected with Dra I is weakly ass ociated with elite endurance athlete status, and we conclude that genetic v ariation in the ADRA2A gene or a locus in close proximity may play a role i n being able to sustain the endurance training regimen necessary to attain a high level of maximal aerobic power.