Ankle sprains are one of the most severe musculoskeletal soft tissue injuries during physical activity. Although many risk factors have been offered, it is unclear why some individuals develop noncontact ankle sprains when participating in comparable levels of physical exertion under identical environmental conditions and others do not. The ACTN3 gene that encodes the α-actinin-3 protein, which is, only expressed in the Z line of fast glycolytic muscle fibres was found to associate with power/strength performance. The aim of this study was therefore to investigate whether the ACTN3 gene polymorphism is associated with noncontact acute ankle sprains. One hundred and forty-two participants with clinically diagnosed noncontact acute ankle sprains as well as 280 physically active controls participants without any history of ankle sprains were included in this case-control genetic association study. The RR genotype (odds ratio (OR) = 0.56; 95% confidence interval (CI), 0.32-0.65, P = 0.011) and R allele (OR = 0.64; 95% CI, 0.37-0.68, P = 0.002) of the ACTN3 were significantly low-represented in the acute ankle sprains group compared with the control group. The ACTN3 R577X is associated with acute ankle sprains in Chinese participants in this study. This is the first study to suggest that an individual with a RR genotype is at a decreased risk of acute ankle sprains.
Keywords: ankle sprain; genetics; polymorphism; α-actinin-3.