R allele of ACTN3 R577X gene polymorphism is associated with Elite Indian Boxer Status

Genetic variations are considered important for athletic performance. In this regard, polymorphisms in angiotensin I-converting enzyme (ACE) and α-actinin-3 genes are widely studied for their association with elite athlete status. The ACE gene regulates circulatory homeostasis, with the I variant of the ACE insertion/deletion (ACE I/D) gene polymorphism being associated with endurance performance, while the R allele of the R577X polymorphism of the ACTN3 gene, crucial for fast glycolytic muscle fibers, has been associated with speed and power performances. The present study investigated the association of these genetic variants with elite boxer (N=57) status and compared it with elite power/speed athletes (N=40), endurance athletes (N=44) and nonathletes (N=98) in the Indian population. The R allele frequency was found significantly higher in boxers than the nonathletes ( p < 0.05). The allele and genotype frequencies of boxers, endurance and power/speed athletes did not differ significantly ( p > 0.05). After analyzing overall athletic cohort on the basis of their level of performance, the frequency of RR genotype (24.1%) and R allele (47.7%) in national level athletes was found significantly higher than in nonathletes (8.7% and 34.2%, respectively), with the significant difference ( p < 0.05) between national level endurance athletes and nonathletes only. The ACE I/D gene polymorphism was not found associated with any of the athletic cohorts ( p > 0.05). Taken altogether, our study showed that the R allele of ACTN3 gene polymorphism is associated with elite boxer status as compared to the nonathletes. Highlights Boxers had a higher ACTN3 gene R allele frequency than nonathletes; genotype did not differ. Boxers with RR genotype had more than 3x higher odds versus nonathletes ( p = 0.02) in the X dominant model (RR vs RX+XX). ACTN3 gene allele and genotype frequencies differed between overall athletic cohort and nonathletes. ACE gene frequencies showed no difference or association across athletic cohorts.