ACTN3 c.1729C>T Polymorphism Might Not Be a Standalone Factor in Non-contact Musculoskeletal Injury: A Systematic Review and Meta-analysis.

backgroundTo date, multiple studies have presented the association of the c.1729C>T polymorphism in the ACTN3 gene with non-contact musculoskeletal injuries, but there are discrepancies and a lack of consensus in this area of research.

objectiveThe aim of this systematic review and meta-analysis was to determine the influence of genotypes and alleles in the c.1729C>T polymorphism of the ACTN3 gene on the incidence and severity of non-contact musculoskeletal injuries in male and female athletes in different sports disciplines.

methodsAn exhaustive literature search was carried out through PubMed, Embase, SPORTDiscus, and Web of Science databases. Longitudinal and cross-sectional studies involving injury rate, severity and association with the c.1729C>T polymorphism of the ACTN3 gene were included in the search. Records were screened by title and abstract and the risk of bias was assessed applying the Newcastle-Ottawa Scale (NOS) to the selected studies. Meta-analyses using RevMan 5.4.1 software were conducted on the following outcomes: non-contact musculoskeletal injury incidence, severity, sex bias, and sport modality.

resultsTen studies examining the association of the ACTN3 gene with the epidemiological characteristics of musculoskeletal injuries were included in the qualitative and quantitative synthesis (1169 subjects) and were analyzed for genotype, allele, dominant and recessive models in injury incidence, severity, sex bias, and sport modality. A significant difference in severity was observed between the CT and TT genotypes (odds ratio [OR]) 0.39; 95% confidence interval (CI) 0.19-0.78; p = 0.008). Additionally, under the recessive model, the TT genotype was significantly associated with a higher risk of non-contact musculoskeletal injuries compared to the combined CT + CC genotypes (OR 2.55; 95% CI 1.23-5.30; p = 0.01). No significant associations were found for injury incidence, severity, sex differences, or sport modality in the other models analyzed.

conclusionCurrently, there is no significant evidence supporting a consistent association between the ACTN3 gene and the incidence of non-contact musculoskeletal injuries. However, our findings suggest that the TT genotype may be associated with greater injury severity under a recessive model. Given the high heterogeneity among studies, these results should be interpreted with caution. Further research using standardized methodologies and larger cohorts is warranted to clarify the potential role of ACTN3 in injury risk and severity.