The -9 /+9 Polymorphism of the Bradykinin Receptor Beta 2 Gene and Athlete Status: A Study Involving Two European Cohorts

Influence of genetic polymorphism on sports talent performance versus non-athletes: a systematic review and meta-analysis

BACKGROUND

Talented athletes exhibit remarkable skills and performance in their respective sports, setting them apart from their peers. It has been observed that genetic polymorphisms can influence variations in sports performance, leading to numerous studies aimed at validating genetic markers for identifying sports talents. This study aims to evaluate the potential contribution of genetic factors associated with athletic performance predisposition in identifying sports talents.

METHODS

A systematic review was conducted following the PRISMA framework, utilizing the PICO methodology to develop the research question. The search was limited to case-control studies published between 2003 and June 2024, and databases such as Medline, LILACS, WPRIM, IBECS, CUMED, VETINDEX, Web of Science, Science Direct, Scopus and Scielo were utilized. The STREGA tool was employed to assess the quality of the selected studies.

RESULTS

A total of 1,132 articles were initially identified, of which 119 studies were included in the review. Within these studies, 50 genes and 94 polymorphisms were identified, showing associations with sports talent characteristics such as endurance, strength, power, and speed. The most frequently mentioned genes were ACTN3 (27.0%) and ACE (11.3%).

CONCLUSION

The ACE I/D and ACTN3 R577X polymorphisms are frequently discussed in the literature. Although athletic performance may be influenced by different genetic polymorphisms, limitations exist in associating them with athletic performance across certain genotypes and phenotypes. Future research is suggested to investigate the influence of polymorphisms in elite athletes from diverse backgrounds and sports disciplines.

Association analysis of indel variants and gene expression identifies MDM4 as a novel locus for skeletal muscle hypertrophy and power athlete status

Insertions and deletions (indels) are the second most common type of variation in the human genome. However, limited data on their associations with exercise-related phenotypes have been documented. The aim of the present study was to examine the association between 18,370 indel variants and power athlete status, followed by additional studies in 357,246 individuals. In the discovery phase, the D allele of the MDM4 gene rs35493922 I/D polymorphism was over-represented in power athletes compared with control subjects (P = 7.8 × 10-9) and endurance athletes (P = 0.0012). These findings were replicated in independent cohorts, showing a higher D allele frequency in power athletes compared with control subjects (P = 0.016) and endurance athletes (P = 0.031). Furthermore, the D allele was positively associated (P = 0.0013) with greater fat-free mass in the UK Biobank. MDM4 encodes a protein that inhibits the activity of p53, which induces muscle fibre atrophy. Accordingly, we found that MDM4 expression was significantly higher in the vastus lateralis of power athletes compared with endurance athletes (P = 0.0009) and was positively correlated with the percentage of fast-twitch muscle fibres (P = 0.0062) and the relative area occupied by fast-twitch muscle fibres (P = 0.0086). The association between MDM4 gene expression and an increased proportion of fast-twitch muscle fibres was confirmed in two additional cohorts. Finally, we found that the MDM4 DD genotype was associated with increased MDM4 gene expression in vastus lateralis and greater cross-sectional area of fast-twitch muscle fibres. In conclusion, MDM4 is suggested to be a potential regulator of muscle fibre specification and size, with its indel variant being associated with power athlete status. HIGHLIGHTS: What is the central question of this study? Which indel variants are functional and associated with sport- and exercise-related traits? What is the main finding and its importance? Out of 18,370 tested indels, the MDM4 gene rs35493922 I/D polymorphism was found to be the functional variant (affecting gene expression) and the most significant, with the deletion allele showing associations with power athlete status, fat-free mass and cross-sectional area of fast-twitch muscle fibres. Furthermore, the expression of MDM4 was positively correlated with the percentage of fast-twitch muscle fibres and the relative area occupied by fast-twitch muscle fibres.

Genetics of long-distance runners and road cyclists-A systematic review with meta-analysis

The aim of this systematic review and meta-analysis was to identify the genetic variants of (inter)national competing long-distance runners and road cyclists compared with controls. The Medline and Embase databases were searched until 15 November 2021. Eligible articles included genetic epidemiological studies published in English. A homogenous group of endurance athletes competing at (inter)national level and sedentary controls were included. Pooled odds ratios based on the genotype frequency with corresponding 95% confidence intervals (95%CI) were calculated using random effects models. Heterogeneity was addressed by Q-statistics, and I² . Sources of heterogeneity were examined by meta-regression and risk of bias was assessed with the Clark Baudouin scale. This systematic review comprised of 43 studies including a total of 3938 athletes and 10 752 controls in the pooled analysis. Of the 42 identified genetic variants, 13 were investigated in independent studies. Significant associations were found for five polymorphisms. Pooled odds ratio [95%CI] favoring athletes compared with controls was 1.42 [1.12-1.81] for ACE II (I/D), 1.66 [1.26-2.19] for ACTN3 TT (rs1815739), 1.75 [1.34-2.29] for PPARGC1A GG (rs8192678), 2.23 [1.42-3.51] for AMPD1 CC (rs17602729), and 2.85 [1.27-6.39] for HFE GG + CG (rs1799945). Risk of bias was low in 25 (58%) and unclear in 18 (42%) articles. Heterogeneity of the results was low (0%-20%) except for HFE (71%), GNB3 (80%), and NOS3 (76%). (Inter)national competing runners and cyclists have a higher probability to carry specific genetic variants compared with controls. This study confirms that (inter)national competing endurance athletes constitute a unique genetic make-up, which likely contributes to their performance level.

Advances in sports genomics

Sports genomics is the scientific discipline that focuses on the organization and function of the genome in elite athletes, and aims to develop molecular methods for talent identification, personalized exercise training, nutritional need and prevention of exercise-related diseases. It postulates that both genetic and environmental factors play a key role in athletic performance and related phenotypes. This update on the panel of genetic markers (DNA polymorphisms) associated with athlete status and soft-tissue injuries covers advances in research reported in recent years, including one whole genome sequencing (WGS) and four genome-wide association (GWAS) studies, as well as findings from collaborative projects and meta-analyses. At end of 2020, the total number of DNA polymorphisms associated with athlete status was 220, of which 97 markers have been found significant in at least two studies (35 endurance-related, 24 power-related, and 38 strength-related). Furthermore, 29 genetic markers have been linked to soft-tissue injuries in at least two studies. The most promising genetic markers include HFE rs1799945, MYBPC3 rs1052373, NFIA-AS2 rs1572312, PPARA rs4253778, and PPARGC1A rs8192678 for endurance; ACTN3 rs1815739, AMPD1 rs17602729, CPNE5 rs3213537, CKM rs8111989, and NOS3 rs2070744 for power; LRPPRC rs10186876, MMS22L rs9320823, PHACTR1 rs6905419, and PPARG rs1801282 for strength; and COL1A1 rs1800012, COL5A1 rs12722, COL12A1 rs970547, MMP1 rs1799750, MMP3 rs679620, and TIMP2 rs4789932 for soft-tissue injuries. It should be appreciated, however, that hundreds and even thousands of DNA polymorphisms are needed for the prediction of athletic performance and injury risk.

Previous experience, aerobic capacity and body composition are the best predictors for Olympic distance triathlon performance: Predictors in amateur triathlon

OBJECTIVE

Present study examines predictors of the overall race time and disciplines in the Olympic distance triathlon.

METHODS

Thirty-nine male and six female triathletes were evaluated for anthropometric, physiological, genetic, training, clinical and circadian characteristics. Body composition, maximum capacity for oxygen uptake (V˙O_2max), maximum aerobic velocity (MAV), anaerobic threshold (AT), triathlon experience (TE) and XX genotype for α-actinin 3 affected total race time (p<0.05).

RESULTS

Total race time can be predicted by MAV (ß = -0.430, t = -3.225, p = 0.003), TE (ß = -0.378, t = -3.605, p = 0.001), and percentage of lean mass (%LM) (ß = -0.332, t = -2.503, p = 0.017). Swimming can be predicted by MAV (ß = -0.403, t = -3.239, p = 0.002), TE (ß = -0.339, t = -2.876, p = 0.007), and AT%V˙O_2max (ß = 0.281, t = 2.278, p = 0.028). Cycling can be predicted by MAV (ß = -0.341, t = -2.333, p = 0.025), TE (ß = -0.363, t = -3.172, p = 0.003), and %LM (ß = -0.326, t = -2.265, p = 0.029). In running split, MAV (ß = -0.768, t = -6.222, p < 0.001) was the only parameter present in the best multiple linear regression model.

CONCLUSION

The most important variables in multiple regression models for estimating performance were MAV, TE, AT and %LM.

Polygenic Study of Endurance-Associated Genetic Markers NOS3 (Glu298Asp), BDKRB2 (-9/+9), UCP2 (Ala55Val), AMPD1 (Gln45Ter) and ACE (I/D) in Polish Male Half Marathoners

The purpose of this study was to investigate individually and in combination the association between the ACE (I/D), NOS3 (Glu298Asp), BDKRB2 (-9/+9), UCP2 (Ala55Val) and AMPD1 (Gln45Ter) variants with endurance performance in a large, performance-homogenous cohort of elite Polish half marathoners. The study group consisted of 180 elite half marathoners: 76 with time < 100 minutes and 104 with time > 100 minutes. DNA of the subjects was extracted from buccal cells donated by the runners and genotyping was carried out using an allelic discrimination assay with a C1000 Touch Thermal Cycler (Bio-Rad, Germany) instrument with TaqMan® probes (NOS3, UCP2, and AMPD1) and a T100™ Thermal Cycler (Bio-Rad, Germany) instrument (ACE and BDKRB2). We found that the UCP2 Ala55Val polymorphism was associated with running performance, with the subjects carrying the Val allele being overrepresented in the group of most successful runners (<100 min) compared to the >100 min group (84.2 vs. 55.8%; OR = 4.23, p < 0.0001). Next, to assess the combined impact of 4 gene polymorphisms, all athletes were classified according to the number of 'endurance' alleles (ACE I, NOS3 Glu, BDKRB2 -9, UCP2 Val) they possessed. The proportion of subjects with a high (4-7) number of 'endurance' alleles was greater in the better half marathoners group compared with the >100 min group (73.7 vs. 51.9%; OR = 2.6, p = 0.0034). These data suggest that the likelihood of becoming an elite half marathoner partly depends on the carriage of a high number of endurance-related alleles.

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.

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.

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.

AGTR2 gene polymorphism is associated with muscle fibre composition, athletic status and aerobic performance

Muscle fibre type is a heritable trait and can partly predict athletic success. It has been proposed that polymorphisms of genes involved in the regulation of muscle fibre characteristics may predispose the muscle precursor cells of a given individual to be predominantly fast or slow. In the present study, we examined the association between 15 candidate gene polymorphisms and muscle fibre type composition of the vastus lateralis muscle in 55 physically active, healthy men. We found that rs11091046 C allele carriers of the angiotensin II type 2 receptor gene (AGTR2; involved in skeletal muscle development, metabolism and circulatory homeostasis) had a significantly higher percentage of slow-twitch fibres than A allele carriers [54.2 (11.1) versus 45.2 (10.2)%; P = 0.003]. These data indicate that 15.2% of the variation in muscle fibre composition of the vastus lateralis muscle can be explained by the AGTR2 genotype. Next, we investigated the frequencies of the AGTR2 alleles in 2178 Caucasian athletes and 1220 control subjects. The frequency of the AGTR2 C allele was significantly higher in male and female endurance athletes compared with power athletes (males, 62.7 versus 51.7%, P = 0.0038; females, 56.6 versus 48.1%, P = 0.0169) and control subjects (males, 62.7 versus 51.0%, P = 0.0006; elite female athletes, 65.1 versus 55.2%, P = 0.0488). Furthermore, the frequency of the AGTR2 A allele was significantly over-represented in female power athletes (51.9%) in comparison to control subjects (44.8%, P = 0.0069). We also found that relative maximal oxygen consumption was significantly greater in male endurance athletes with the AGTR2 C allele compared with AGTR2 A allele carriers [n = 28; 62.3 (4.4) versus 57.4 (6.0) ml min(-1) kg(-1); P = 0.0197]. Taken together, these results demonstrate that the AGTR2 gene C allele is associated with an increased proportion of slow-twitch muscle fibres, endurance athlete status and aerobic performance, while the A allele is associated with a higher percentage of fast-twitch fibres and power-oriented disciplines.