Effect of ACTN3 Genotype on Sports Performance, Exercise-Induced Muscle Damage, and Injury Epidemiology

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first_pagesettingsOrder Article Reprints Open AccessDiscussion Effect of ACTN3 Genotype on Sports Performance, Exercise-Induced Muscle Damage, and Injury Epidemiology Chat with paper by Gabriel Baltazar-Martins 1ORCID,Jorge Gutiérrez-Hellín 2ORCID,Millán Aguilar-Navarro 1,2ORCID,Carlos Ruiz-Moreno 1ORCID,Victor Moreno-Pérez 3,Álvaro López-Samanes 2ORCID,Raúl Domínguez 4ORCID andJuan Del Coso 5,*ORCID 1 Exercise Physiology Laboratory, Camilo José Cela University, 28692 Madrid, Spain 2 Faculty of Health Sciences, Universidad Francisco de Vitoria, 28223 Madrid, Spain 3 Centre for Translational Research in Physiotherapy, Universidad Miguel Hernández, 03202 Elche, Spain 4 College of Health Sciences, Isabel I University, 09003 Burgos, Spain 5 Centre for Sport Studies, Rey Juan Carlos University, 28943 Fuenlabrada, Spain * Author to whom correspondence should be addressed. Sports 2020, 8(7), 99; https://doi.org/10.3390/sports8070099 Received: 28 May 2020 / Revised: 30 June 2020 / Accepted: 9 July 2020 / Published: 13 July 2020 Downloadkeyboard_arrow_down Browse Figure Versions Notes Abstract Genetic factors play a significant role in athletic performance and its related phenotypes such as power, strength and aerobic capacity. In this regard, the lack of a muscle protein due to a genetic polymorphism has been found to affect sport performance in a wide variety of ways. α-actinin-3 is a protein located within the skeletal muscle with a key role in the production of sarcomeric force. A common stop-codon polymorphism (rs1815739; R577X) in the gene that codes for α-actinin-3 (ACTN3) produces individuals with the XX genotype that lack expression of a functional α-actinin-3. In contrast, individuals with the R-allele (i.e., RX vs. RR genotypes) in this polymorphism can express α-actinin-3. Interestingly, around ~18% of the world population have the XX genotype and much has been debated about why a polymorphism that produces a lack of a muscle protein has endured natural selection. Several investigations have found that α-actinin-3 deficiency due to XX homozygosity in the ACTN3 R577X polymorphism can negatively affect sports performance through several structural, metabolic, or signaling changes. In addition, new evidence suggests that α-actinin-3 deficiency may also impact sports performance through indirect factors such a higher risk for injury or lower resistance to muscle-damaging exercise. The purpose of this discussion is to provide a clear explanation of the effect of α-actinin-3 deficiency due to the ACTN3 XX genotype on sport. Key focus has been provided about the effect of α-actinin-3 deficiency on morphologic changes in skeletal muscle, on the low frequency of XX athletes in some athletic disciplines, and on injury epidemiology.