Background Previous research has shown that variants in the AMPD1 gene, which encodes the adenosine monophosphate deaminase 1 (AMPD1) protein, may affect energy supply of the muscle and fatigue resistance during high-intensity exercise. A single nucleotide substitution in this gene, specifically a cytosine-to-thymine substitution (c.34C > T; rs17602729), results in a nonsense mutation that causes a deficiency in the AMPD1 protein. Deficiency of the AMPD1 protein due to this polymorphism can influence exercise performance, ultimately affecting the likelihood of reaching the status of elite endurance or power athlete. Objective This systematic review and meta-analysis aimed to investigate the distribution of CC, CT, and TT genotypes of the AMPD1 c.34C > T polymorphism (rs17602729) in endurance and power athletes to assess potential associations between this polymorphism and elite athlete status. Methods Studies investigating genotype distribution in the AMPD1 c.34C > T (rs17602729) polymorphism in endurance and/or power athletes were searched for in four electronic databases (PubMed, Web of Science, Scopus, Science Direct). The studies were selected and the genotypic and allelic frequencies of the AMPD1 c.34C > T (rs17602729) polymorphism were extracted if data for endurance and/or power athletes were compared with controls (non-athletes). Meta-analyses were computed using fixed or random effects models to calculate odds ratios (OR) with confidence interval (95% CI). Heterogeneity of the meta-analyses was reported using I2 statistics. Results After examining 1229 studies on the distribution of the AMPD1 c.34C > T (rs17602729) polymorphism in endurance and/or power athletes, 20 studies were considered eligible to be included in our meta-analysis. The studies were conducted in 11 different countries, including 5717 participants. There was a higher frequency of the CC genotype (OR 1.72; 95% CI 1.40–2.12; p < 0.00001) in endurance athletes compared with non-athletic controls with a lower frequency of CT (OR 0.61; 95% CI 0.49–0.75; p < 0.00001) and TT genotypes in endurance athletes versus non-athletic controls (OR 0.43; 95% CI 0.19–0.97; p = 0.04). A higher frequency of the CC genotype was also observed in power athletes compared with controls (OR 2.17; 95% CI 1.69–2.78; p < 0.00001) with a lower frequency of the CT (OR 0.51; 95% CI 0.39–0.65; p < 0.00001) and TT genotypes (OR 0.25; 95% CI 0.09–0.68; p = 0.007) in power athletes compared with controls. Overall, the genotype distribution of the AMPD1 c.34C > T polymorphism (rs17602729) was similar in endurance and power athletes (OR between 0.76 and 1.39; p = 0.47–0.72). Conclusion Our findings indicate that the CC genotype was overrepresented in endurance and power athletes compared with controls, suggesting that possessing two copies of the C allele of the AMPD1 c.34C > T (rs17602729) polymorphism may be associated with a 1.72–2.17 times greater likelihood of achieving elite or sub-elite athlete status in disciplines reliant on aerobic and anaerobic metabolic pathways. No statistically significant differences were found in the AMPD1 genotype distribution between endurance and power athletes.
