Genes in sport and doping

The Effect of Selected Polymorphisms of the ACTN3, ACE, HIF1A and PPARA Genes on the Immediate Supercompensation Training Effect of Elite Slovak Endurance Runners and Football Players

We aimed to evaluate the effect of selected polymorphisms of the ACTN3, ACE, HIF1A and PPARA genes on the immediate supercompensation training effect of elite Slovak endurance runners and football players compared with a sedentary control group. Adaptation effect levels were evaluated by 10 s continuous vertical jump test parameters measured by Optojump. Genetic polymorphisms were determined by PCR and Sanger sequencing. We found significant differences in the effect of PPARA genotypes in the experimental group. C allele genotypes represented an advantage in immediate supercompensation (p < 0.05). We observed a significant combined effect of multiple genes on immediate supercompensation (p < 0.05): the RR genotype of the ACTN3 gene, the ID genotype of the ACE gene, the Pro/Pro genotype of HIF1A, and the GC and GG genotypes of PPARA genes. In the control group, we found a significant effect (p < 0.05) on immediate supercompensation of the II genotype of the ACE gene and the Pro/Ser genotype of the HIF1A gene. We found significant differences in genotype frequency of ACE (p < 0.01) and PPARA (p < 0.001) genes. We confirmed that individual genetic polymorphisms of ACTN3, ACE, HIF1A and PPARA genes have a different effect on the level of immediate supercompensation of the lower limbs depending on the training adaptation of the probands and the combination of genotypes.

Genetics and sports performance: the present and future in the identification of talent for sports based on DNA testing

The impact of genetics on physiology and sports performance is one of the most debated research aspects in sports sciences. Nearly 200 genetic polymorphisms have been found to influence sports performance traits, and over 20 polymorphisms may condition the status of the elite athlete. However, with the current evidence, it is certainly too early a stage to determine how to use genotyping as a tool for predicting exercise/sports performance or improving current methods of training. Research on this topic presents methodological limitations such as the lack of measurement of valid exercise performance phenotypes that make the study results difficult to interpret. Additionally, many studies present an insufficient cohort of athletes, or their classification as elite is dubious, which may introduce expectancy effects. Finally, the assessment of a progressively higher number of polymorphisms in the studies and the introduction of new analysis tools, such as the total genotype score (TGS) and genome-wide association studies (GWAS), have produced a considerable advance in the power of the analyses and a change from the study of single variants to determine pathways and systems associated with performance. The purpose of the present study was to comprehensively review evidence on the impact of genetics on endurance- and power-based exercise performance to clearly determine the potential utility of genotyping for detecting sports talent, enhancing training, or preventing exercise-related injuries, and to present an overview of recent research that has attempted to correct the methodological issues found in previous investigations.

Perspectives in Sports Genomics

Human athletic performance is a complex phenotype influenced by environmental and genetic factors, with most exercise-related traits being polygenic in nature. The aim of this article is to outline some of the challenge faced by sports genetics as this relatively new field moves forward. This review summarizes recent advances in sports science and discusses the impact of the genome, epigenome and other omics (such as proteomics and metabolomics) on athletic performance. The article also highlights the current status of gene doping and examines the possibility of applying genetic knowledge to predict athletes’ injury risk and to prevent the rare but alarming occurrence of sudden deaths during sporting events. Future research in large cohorts of athletes has the potential to detect new genetic variants and to confirm the previously identified DNA variants believed to explain the natural predisposition of some individuals to certain athletic abilities and health benefits. It is hoped that this article will be useful to sports scientists who seek a greater understanding of how genetics influences exercise science and how genomic and other multi-omics approaches might support performance analysis, coaching, personalizing nutrition, rehabilitation and sports medicine, as well as the potential to develop new rationale for future scientific investigation.

Effects of Genetic Variation on Endurance Performance, Muscle Strength, and Injury Susceptibility in Sports: A Systematic Review

The aim of this systematic review was to assess the effects of genetic variations and polymorphisms on endurance performance, muscle strength and injury susceptibility in competitive sports. The electronic databases PubMed and Web of Science were searched for eligible studies. The study quality was assessed using the RoBANS tool. Studies were included if they met the following criteria: (1) human study in English or German; (2) published in the period 2015–2019; (3) investigation of an association between genetic variants and endurance performance and/or muscle strength and/or endurance/strength training status as well as ligament, tendon, or muscle injuries; (4) participants aged 18–60 years and national or international competition participation; (5) comparison with a control group. Nineteen studies and one replication study were identified. Results revealed that the IGF-1R 275124 A>C rs1464430 polymorphism was overrepresented in endurance trained athletes. Further, genotypes of PPARGC1A polymorphism correlated with performance in endurance exercise capacity tests in athletes. Moreover, the RR genotype of ACTN3 R577X polymorphism, the C allele of IGF-1R polymorphism and the gene variant FTO T>A rs9939609 and/or their AA genotype were linked to muscle strength. In addition, gene variants of MCT1 (T1470A rs1049434) and ACVR1B (rs2854464) were also positively associated with strength athletes. Among others, the gene variants of the MMP group (rs591058 and rs679620) as well as the polymorphism COL5A1 rs13946 were associated with susceptibility to injuries of competitive athletes. Based on the identified gene variants, individualized training programs for injury prevention and optimization of athletic performance could be created for competitive athletes using gene profiling techniques.

Gene doping: Present and future

Being an elite athlete is an extremely coveted position, which can lead an individual to use doping. As knowledge is extended, doping techniques have become increasingly sophisticated, and the newest method of doping is gene doping. This article aims to present an updated bibliographic survey that addresses gene doping between 1983 and 2018. Anti-doping agencies have not yet approved any detection technique for this type of doping. The possibility of eradicating such doping is almost zero mainly because gene therapy advances rapidly. In this scenario, the future of gene doping must be discussed and decided before irreversible limits are exceeded.

Individual and Combined Influence of ACE and ACTN3 Genes on Muscle Phenotypes in Polish Athletes

Orysiak, J, Mazur-Różycka, J, Busko, K, Gajewski, J, Szczepanska, B, and Malczewska-Lenczowska, J. Individual and combined influence of ACE and ACTN3 genes on muscle phenotypes in polish athletes. J Strength Cond Res 32(10): 2776-2782, 2018-The aim of this study was to examine the association between angiotensin-converting enzyme (ACE) and α-actinin-3 (ACTN3) genes, independently or in combination, and muscle strength and power in male and female athletes. The study involved 398 young male (n = 266) and female (n = 132) athletes representing various sport disciplines (ice hockey, canoeing, swimming, and volleyball). All were Caucasians. The following measurements were taken: height of jump and mechanical power in countermovement jump (CMJ) and spike jump (SPJ), and muscle strength of 10 muscle groups (flexors and extensors of the elbow, shoulder, hip, knee, and trunk). The insertion-deletion (I/D) polymorphism of ACE and the R577X polymorphism of ACTN3 were typed using polymerase chain reaction (PCR) and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), respectively. The genotype distribution of the ACE and ACTN3 genes did not differ significantly between groups of athletes for either sex. There was no association between ACE and ACTN3 genotypes (alone or in combination) and sum of muscle strength, height of jump or mechanical power in both jump tests (CMJ and SPJ) for male and female athletes. These findings do not support an influential role of the ACE and ACTN3 genes in determining power/strength performance of elite athletes.

The potential role of myostatin and neurotransmission genes in elite sport performances

Elite athletes are those who represent their sport at such major competition as the Olympic Games or World contests. The most outstanding athletes appear to emerge as a result of endogenous biologic characteristics interacting with exogenous influences of the environment, often described as a 'Nature and Nurture' struggle. In this work, we assessed the contribution given by 4 genes involved in muscles development (MSTN) and behavioural insights (5HTT, DAT and MAOA) to athletic performances. As for neurotransmission, 5HTT, DAT and MAOA genes have been considered as directly involved in the management of aggressiveness and anxiety. Genotypes and allelic frequencies of 5HTTLPR, MAOA-u VNTR, DAT VNTR and MSTN K153R were determined in 50 elite athletes and compared with 100 control athletes. In this work we found a significant correlation between the dopamine transporter genotype 9/9 and allele 9 and elite sport performances. On the contrary, no association was found between muscle development regulation or serotonin pathway and elite performances. Our data, for the first time, suggest a strong role of dopamine neurotransmitter in determining sport success, highlighting the role of emotional control and psycological management to reach high-level performances.

Effect of BDKRB2 Gene -9/+9 Polymorphism on Training Improvements in Competitive Swimmers

The aim of the study was to investigate the possible association between the BDKRB2 gene and training-induced improvements in swimming performance in well-trained swimmers. One hundred Polish swimmers (52 men and 48 women, aged 18.1 ± 1.9 years), who competed in national and international competitions at middle- (200 m) and long-distance events (≥400 m), were included in the study. Athletes' genotype and allele distributions were analyzed in comparison to 230 unrelated sedentary subjects, who served as controls, with the χ test. All samples were genotyped for the BDKRB2 -9/+9 polymorphism by polymerase chain reaction. The effects of genotype on swimming performance improvements were analyzed with two-way (3 × 2; genotype × time) analysis of variance with metric age as a covariate. The training period of 1.9 ± 0.4 years had a significant (p < 0.01) effect on swimming performance, both in female and male athletes. Both in female and male athletes, the BDKRB2 gene -9/+9 polymorphism had no significant effect on swimming performance. An interaction effect of BDKRB2 gene -9/+9 polymorphism × time was found for swimming performance only in male athletes. Post hoc analyses showed that swimmers with the +9/+9 BDKRB2 genotype had a greater improvement in swimming performance than swimmers with the -9/+9 polymorphism (p ≤ 0.05). No interaction effects for gender × BDKRB2 gene -9/+9 polymorphism were found for either swimming performance or improvement in swimming performance. These results suggest that the response to long-term exercise training could be modulated by the BDKRB2 gene -9/+9 polymorphism in male athletes. In well-trained swimmers, BDKRB2 gene variation was not found to be an independent determinant of swimming performance.

Distribution of Angiotensin-1 Converting Enzyme Insertion/Deletion and α-Actinin-3 Codon 577 Polymorphisms in Turkish Male Soccer Players

Angiotensin-1 converting enzyme (ACE) gene and α-actinin-3 (ACTN3) gene polymorphisms are considered to be the most important candidate genes for genetic predisposition to human athletic performance. In the present study, we aimed to analyze the distribution of ACE and ACTN3 polymorphisms for the first time in male Turkish soccer players. In this prospective study, our cohort consisted of 25 professional players, all with Turkish ancestry. Polymerase chain reaction (PCR)-restriction length polymorphism was used for the characterization of the genotype of ACTN3 and single PCR for ACE. For ACE genotype, 16%, 44%, and 40% of the players had insertion/insertion (II), insertion/deletion (ID), and deletion/deletion (DD) genotypes, respectively, whereas 20% had XX, 36% had RX, and 44% had RR genotypes for ACTN3. When we examined the allelic percentages, for ACE, D allele was recorded as 62 and I as 38, and for ACTN3, R allele was 62 and X was 38. Our results were in agreement with the previous reports, indicating the presence of ACTN3 D and ACE X allele in soccer players. We suggest that ACE and ACTN3 genotypes are important biomarkers for genetic counseling for the individuals who are prone to be successful soccer players.

Doping with anabolic androgenic steroids (AAS): Adverse effects on non-reproductive organs and functions

Since the 1970s anabolic androgenic steroids (AAS) have been abused at ever increasing rates in competitive athletics, in recreational sports and in bodybuilding. Exceedingly high doses are often consumed over long periods, in particular by bodybuilders, causing acute or chronic adverse side effects frequently complicated by additional polypharmacy. This review summarizes side effects on non-reproductive organs and functions; effects on male and female reproduction have been recently reviewed in a parallel paper. Among the most striking AAS side effects are increases in haematocrit and coagulation causing thromboembolism, intracardiac thrombosis and stroke as well as other cardiac disturbances including arrhythmias, cardiomyopathies and possibly sudden death. 17α-alkylated AAS are liver toxic leading to cholestasis, peliosis, adenomas and carcinomas. Hyperbilirubinaemia can cause cholemic nephrosis and kidney failure. AAS abuse may induce exaggerated self-confidence, reckless behavior, aggressiveness and psychotic symptoms. AAS withdrawal may be accompanied by depression and suicidal intentions. Since AAS abuse is not or only reluctantly admitted physicians should be aware of the multitude of serious side effects when confronted with unclear symptoms.

Overrepresentation of the ACTN3 XX genotype in elite canoe and kayak paddlers

The aim of the study was to examine the association between the ACTN3 R577X polymorphism in canoe sprint athletes (canoe and kayak paddlers) and their results at 200- or 1000-m distance. Eighty-six European white male athletes divided into 2 groups-successful, who were outstanding at national championships, and nonsuccessful in these competitions-and 354 nonathletic controls were included in this study. The R577X polymorphism of ACTN3 was typed using PCR-RFLP. ACTN3 genotype distribution among all tested athletes and controls was in Hardy-Weinberg equilibrium. The odds ratio (OR) for successful 1000-m athletes harboring the XX genotype compared with sedentary controls was 2.95 (95% confidence interval [CI]: 1.37-6.35), but the OR for nonsuccessful 200-m athletes having the XX genotype compared with controls was 2.64 (95% CI: 1.30-5.36). These results suggest that factors associated with the ACTN3 XX genotype in canoe and kayak paddlers might provide some competitive advantage in performance at 1000 m, but it seems to limit at 200 m. Further studies aimed at development of training strategies based on genetic factors are needed.

Overrepresentation of the COL3A1 AA genotype in Polish skiers with anterior cruciate ligament injury

Although various intrinsic and extrinsic risk factors for anterior cruciate ligament (ACL) rupture have been identified, the exact aetiology of the injury is not yet fully understood. Type III collagen is an important factor in the repair of connective tissue, and certain gene polymorphisms may impair the tensile strength. The aim of this study was to examine the association of the COL3A1 rs1800255 polymorphism with ACL rupture in Polish male recreational skiers. A total of 321 male Polish recreational skiers were recruited for this study; 138 had surgically diagnosed primary ACL ruptures (ACL-injured group) and 183 were apparently healthy male skiers (control group – CON) who had no self-reported history of ligament or tendon injury. Both groups had a comparable level of exposure to ACL injury. Genomic DNA was extracted from the oral epithelial cells. All samples were genotyped on a real-time polymerase chain reaction instrument. The genotype distribution in the ACL-injured group was significantly different than in CON (respectively: AA=10.1 vs 2.2%, AG=22.5 vs 36.1, GG=67.4 vs 61.8%; p=0.0087). The AA vs AG+GG genotype of COL3A1 (odds ratio (OR)=5.05; 95% confidence interval (CI), 1.62-15.71, p=0.003) was significantly overrepresented in the ACL-injured group compared with CON. The frequency of the A allele was higher in the ACL-injured group (21.4%) compared with CON (20.2%), but the difference was not statistically significant (p=0.72). This study revealed an association between the COL3A1 rs1800255 polymorphism and ACL ruptures in Polish skiers.

Current Progress in Sports Genomics

Understanding the genetic architecture of athletic performance is an important step in the development of methods for talent identification in sport. Research concerned with molecular predictors has highlighted a number of potentially important DNA polymorphisms contributing to predisposition to success in certain types of sport. This review summarizes the evidence and mechanistic insights on the associations between DNA polymorphisms and athletic performance. A literature search (period: 1997-2014) revealed that at least 120 genetic markers are linked to elite athlete status (77 endurance-related genetic markers and 43 power/strength-related genetic markers). Notably, 11 (9%) of these genetic markers (endurance markers: ACE I, ACTN3 577X, PPARA rs4253778 G, PPARGC1A Gly482; power/strength markers: ACE D, ACTN3 Arg577, AMPD1 Gln12, HIF1A 582Ser, MTHFR rs1801131 C, NOS3 rs2070744 T, PPARG 12Ala) have shown positive associations with athlete status in three or more studies, and six markers (CREM rs1531550 A, DMD rs939787 T, GALNT13 rs10196189 G, NFIA-AS1 rs1572312 C, RBFOX1 rs7191721 G, TSHR rs7144481 C) were identified after performing genome-wide association studies (GWAS) of African-American, Jamaican, Japanese, and Russian athletes. On the other hand, the significance of 29 (24%) markers was not replicated in at least one study. Future research including multicenter GWAS, whole-genome sequencing, epigenetic, transcriptomic, proteomic, and metabolomic profiling and performing meta-analyses in large cohorts of athletes is needed before these findings can be extended to practice in sport.

Relationship Between ACTN3 R577X Polymorphism and Physical Abilities in Polish Athletes

The purpose of this study was to examine the association between α-actinin 3 (ACTN3) R577X polymorphism and physical abilities of male athletes performing various sports (volleyball, ice hockey, canoeing, swimming). One hundred eighty-five subjects were recruited for the study. The following measurements were taken: height of jump and power output in countermovement jump and spike jump (SPJ) and muscle strength of 10 muscle groups. The R577X polymorphism of ACTN3 was typed using polymerase chain reaction restriction fragment length polymorphism. The results showed that RR genotype carriers develop greater power output in SPJ than RX and XX individuals (44.6 ± 11.1, 42.6 ± 11.0, and 38.4 ± 7.9 W·kg(-1) for RR, RX, and XX genotypes, respectively) and height of jump in SPJ (0.537 ± 0.075, 0.523 ± 0.072, and 0.498 ± 0.053 m for RR, RX, and XX genotypes, respectively). Muscle strength did not differ between genotype groups. This suggests that the ACTN3 gene has a greater impact on determining dynamic movements than influencing static muscle strength.

Does the A9285G Polymorphism in Collagen Type XII α1 Gene Associate with the Risk of Anterior Cruciate Ligament Ruptures?

One of the most severe injuries sustained by athletes is rupture of the anterior cruciate ligament (ACL). Recent investigations suggest that a predisposition for ACL rupture may be the result of specific genetic sequence variants. In light of this, we decided to investigate whether the COL12A1 A9285G polymorphism was associated with ACL ruptures in Polish football players.

We compared genotypic and allelic frequencies of the COL12A1 A9285G polymorphism in two groups of athletes: 91 male football players (23 ± 3 years) with surgically diagnosed primary ACL ruptures who qualified for ligament reconstruction (cases) and 143 apparently healthy, male football players of the same ethnicity, a similar age category, and a comparable level of exposure to ACL injury, who were without any self-reported history of ligament or tendon injury (controls). DNA samples extracted from the oral epithelial cells were genotyped by using a real-time polymerase chain reaction (Ri-Ti-PCR) method.

The genotype distribution in the cases were not different from those in controls (p = 0.70). The frequency of the G allele was lower in the cases (18.1%) but not statistically significant (p = 0.40) when compared with controls (21.3%).

Our results are in contradiction to the hypothesis that the COL12A1 A9285G polymorphism is associated with a predisposition for ACL injury. However, these conclusions should be supported with more experimental studies on COL12A1 polymorphisms.

Gene doping in sport - perspectives and risks

In the past few years considerable progress regarding the knowledge of the human genome map has been achieved. As a result, attempts to use gene therapy in patients' management are more and more often undertaken. The aim of gene therapy is to replace defective genes in vivo and/or to promote the long-term endogenous synthesis of deficient protein. In vitro studies improve the production of human recombinant proteins, such as insulin (INS), growth hormone (GH), insulin-like growth factor-1 (IGF-1) and erythropoietin (EPO), which could have therapeutic application. Unfortunately, genetic methods developed for therapeutic purposes are increasingly being used in competitive sports. Some new substances (e.g., antibodies against myostatin or myostatin blockers) might be used in gene doping in athletes. The use of these substances may cause an increase of body weight and muscle mass and a significant improvement of muscle strength. Although it is proven that uncontrolled manipulation of genetic material and/or the introduction of recombinant proteins may be associated with health risks, athletes are increasingly turning to banned gene doping. At the same time, anti-doping research is undertaken in many laboratories around the world to try to develop and refine ever newer techniques for gene doping detection in sport. Thanks to the World Anti-Doping Agency (WADA) and other sports organizations there is a hope for real protection of athletes from adverse health effects of gene doping, which at the same time gives a chance to sustain the idea of fair play in sport.

Genome-wide association study identifies three novel genetic markers associated with elite endurance performance

To investigate the association between multiple single-nucleotide polymorphisms (SNPs), aerobic performance and elite endurance athlete status in Russians. By using GWAS approach, we examined the association between 1,140,419 SNPs and relative maximal oxygen consumption rate (V.O₂max) in 80 international-level Russian endurance athletes (46 males and 34 females). To validate obtained results, we further performed case-control studies by comparing the frequencies of the most significant SNPs (with P < 10⁻⁵-10⁻⁸) between 218 endurance athletes and opposite cohorts (192 Russian controls, 1367 European controls, and 230 Russian power athletes). Initially, six ‘endurance alleles’ were identified showing discrete associations with V.O₂max both in males and females. Next, case-control studies resulted in remaining three SNPs (NFIA-AS2 rs1572312, TSHR rs7144481, RBFOX1 rs7191721) associated with endurance athlete status. The C allele of the most significant SNP, rs1572312, was associated with high values of V.O₂max (males: P = 0.0051; females: P = 0.0005). Furthermore, the frequency of the rs1572312 C allele was significantly higher in elite endurance athletes (95.5%) in comparison with non-elite endurance athletes (89.8%, P = 0.0257), Russian (88.8%, P = 0.007) and European (90.6%, P = 0.0197) controls and power athletes (86.2%, P = 0.0005). The rs1572312 SNP is located on the nuclear factor I A antisense RNA 2 (NFIA-AS2) gene which is supposed to regulate the expression of the NFIA gene (encodes transcription factor involved in activation of erythropoiesis and repression of the granulopoiesis). Our data show that the NFIA-AS2 rs1572312, TSHR rs7144481 and RBFOX1 rs7191721 polymorphisms are associated with aerobic performance and elite endurance athlete status.

Interaction Between ACE I/D and ACTN3 R557X Polymorphisms in Polish Competitive Swimmers

We hypothesized that the ACE ID / ACTN3 R577X genotype combination was associated with sprint and endurance performance. Therefore, the purpose of the present study was to determine the interaction between both ACE ID and ACTN3 R577X polymorphisms and sprint and endurance performance in swimmers. Genomic DNA was extracted from oral epithelial cells using GenElute Mammalian Genomic DNA Miniprep Kit (Sigma, Germany). All samples were genotyped using a real-time poly- merase chain reaction. The ACE I/D and the ACTN3 R577X genotype frequencies met Hardy-Weinberg expectations in both swimmers and controls. When the two swimmer groups, long distance swimmers (LDS) and short distance swimmers (SDS), were compared with control subjects in a single test, a significant association was found only for the ACE polymorphism, but not for ACTN3. Additionally, four ACE/ACTN3 combined genotypes (ID/RX, ID/XX, II/RX and II/XX) were statistically significant for the LDS versus Control comparison, but none for the SDS versus Control comparison. The ACE I/D and the ACTN3 R577X polymorphisms did not show any association with sprint swimming, taken individually or in combination. In spite of numerous previous reports of associations with athletic status or sprint performance in other sports, the ACTN3 R577X polymorphism, in contrast to ACE I/D, was not significantly associated with elite swimming status when considered individually. However, the combined analysis of the two loci suggests that the co-occurrence of the ACE I and ACTN3 X alleles may be beneficial to swimmers who compete in long distance races.

THE GSTP1 c.313A>G POLYMORPHISM MODULATES THE CARDIORESPIRATORY RESPONSE TO AEROBIC TRAINING

The GSTP1 c.313A>G polymorphism is a candidate to explain some of the individual differences in cardiorespiratory fitness phenotypes’ responses to aerobic exercise training. We aim to explore the association between the GSTP1 c.313A>G polymorphism and the response to low-high impact aerobic exercise training. Sixty-six Polish Caucasian women were genotyped for the GSTP1 c.313A>G polymorphism; 62 of them completed 12-week aerobic (50-75% HR_max) exercise training and were measured for selected somatic features (body mass and BMI) and cardiorespiratory fitness indices – maximal oxygen uptake (VO_2max, maximum heart rate (HR_max), maximum ventilation (V_Emax) and anaerobic threshold (AT) – before and after the training period. Two-factor analysis of variance revealed a main training effect for body mass reduction (p=0.007) and BMI reduction (p=0.013), improvements of absolute and relative VO_2max (both p<0.001), and increased V_Emax (p=0.005), but not for changes in fat-free mass (FFM) (p=0.162). However, a significant training x GSTP1 c.313A>G interaction was found only for FFM (p=0.042), absolute and relative VO_2max (p=0.029 and p=0.026), and V_Emax (p=0.005). As the result of training, significantly greater improvements in VO_2max, V_Emax and FFM were gained by the GG+GA group compared to the AA genotype group. The results support the hypothesis that heterogeneity in individual response to training stimuli is at least in part determined by genetics, and GSTP1 c.313A>G may be considered as one (of what appear to be many) target polymorphisms to influence these changes.

Actn3 genotype is associated with testosterone levels of athletes

α-Actinin-3 (ACTN3) has been proposed to regulate skeletal muscle differentiation and hypertrophy through its interaction with the signalling protein calcineurin. Since the inhibition of calcineurin potentiates the production of testosterone, we hypothesized that α-actinin-3 deficiency (predicted from the ACTN3 XX genotype) may influence serum levels of testosterone of athletes.

OBJECTIVE

To investigate the association of ACTN3 gene R577X polymorphism with resting testosterone levels in athletes.

METHODS

A total of 209 elite Russian athletes from different sports (119 males, 90 females) were genotyped for ACTN3 gene R577X polymorphism by real-time PCR. Resting testosterone was examined in serum of athletes using enzyme immunoassay.

RESULTS

The mean testosterone levels were significantly higher in both males and females with the ACTN3 R allele than in XX homozygotes (males: RR: 24.9 (5.7), RX: 21.8 (5.5), XX: 18.6 (4.9) ng · mL(-1), P = 0.0071; females: RR: 1.43 (0.6), RX: 1.21 (0.71), XX: 0.79 (0.66) ng · mL(-1), P = 0.0167).

CONCLUSIONS

We found that the ACTN3 R allele was associated with high levels of testosterone in athletes, and this may explain, in part, the association between the ACTN3 RR genotype, skeletal muscle hypertrophy and power athlete status.

Bdkrb2 gene -9/+9 polymorphism and swimming performance

The aim of the study was to evaluate the association between swimming performance and the -9/+9 (rs5810761) polymorphism within the BDKRB2 gene in successful competitive swimmers. Best individual swimming results expressed in FINA points achieved at short, middle and long distance events of 157 well-trained Polish swimmers were incorporated into an analysis. Athletes' genotype and allele distributions were analysed in comparison to 230 unrelated sedentary subjects who served as controls with the χ(2) test. All samples were genotyped for the BDKRB2 -9/+9 polymorphism using the polymerase chain reaction (PCR). The effects of genotype on swimming performance were analysed with two-way (3 x 2; genotype x gender) analysis of variance with metrical age as a covariate for each distance specialization. No statistical differences in the genotype and allele frequencies were found in long distance swimmers when compared with the total group of swimmers or controls. The BDKRB2 +9/-9 genotype had no significant effect on swimming performance at short, middle or long distance, regardless of gender. The results of this study do not support the hypothesis that the BDKRB2 -9/+9 polymorphism is associated with swimming performance in Polish swimmers.

NO ASSOCIATION BETWEEN tHbmass AND POLYMORPHISMS IN THE HBB GENE IN ENDURANCE ATHLETES

The aim of this study was to examine the association between tHbmass and HBB gene polymorphisms in athletes of endurance disciplines. Eighty-two well-trained athletes (female n=36, male n=46), aged 19.3 ± 2.7 years, representing cross country skiing (n=37) and middle- and long-distance running (n=45), participated in the study. Genotyping for 2 polymorphisms in the HBB gene (- 551C/T and intron 2, +16 C/G) was performed using restriction fragment length polymorphism analysis. Total haemoglobin mass (tHbmass) was determined by the optimized carbon monoxide rebreathing method. Blood morphology, indices of iron status (ferritin, transferrin receptor and total iron binding capacity) and C reactive protein were also determined. No differences were found in the HBB genotype and allele frequencies between male and female athletes. Regardless of the polymorphisms, no relationships were found between HBB genotypes as well as alleles and relative values of tHbmass, expressed per body mass (g · kg^-1 BM), both in female and male athletes. Our results demonstrated that -551 C/T and intron 2, +16 C/G polymorphisms of the HBB gene have no association with total haemoglobin mass in endurance athletes. It cannot be ruled out that several polymorphisms, each with a small but significant contribution, may be responsible for the amount of haemoglobin.

Is gnb3 c825t polymorphism associated with elite status of polish athletes?

The GNB3 gene encodes the beta 3 subunit of heterotrimeric G-proteins that are key components of intracellular signal transduction between G protein-coupled receptors (GPCR) and intracellular effectors and might be considered as a potential candidate gene for physical performance.

OBJECTIVES

The aim of this study was to compare frequency distribution of the common C to T polymorphism at position 825 (C825T) of the GNB3 gene between athletes and nonathletic controls of the Polish population as well as to compare the genotype distribution and allele frequency of C825T variants within a group of athletes, i.e. between athletes of sports of different metabolic demands and competitive levels.

METHODS

The study was performed in a group of 223 Polish athletes of the highest nationally competitive standard (123 endurance-oriented athletes and 100 strength/ power athletes). Control samples were prepared from 354 unrelated, sedentary volunteers.

RESULTS

The χ(2) test revealed no statistical differences between the endurance-oriented athletes and the control group or between sprint/strength athletes and the control group across the GNB3 825C/T genotypes. There were no male-female genotype or allele frequency differences in controls or in either strength/power or endurance-oriented athletes. No statistically significant differences in either allele frequencies or genotype distribution were noted between the top-elite, elite or sub-elite of endurance-oriented and strength/power athletes and the control group.

CONCLUSIONS

No association between elite status of Polish athletes and the GNB3 C825T polymorphic site has been found.