Association ofACTN3 R577Xbut notACEI/D gene variants with elite rugby union player status and playing position

Abstract

We aimed to quantify the ACE I/D and ACTN3 R577X (rs1815739) genetic variants in elite rugby athletes (rugby union and league) and compare genotype frequencies to controls and between playing positions. The rugby athlete cohort consisted of 507 Caucasian men, including 431 rugby union athletes that for some analyses were divided into backs and forwards and into specific positional groups: front five, back row, half backs, centers, and back three. Controls were 710 Caucasian men and women. Real-time PCR of genomic DNA was used to determine genotypes using TaqMan probes and groups were compared using χ2 and odds ratio (OR) statistics. Correction of P values for multiple comparisons was according to Benjamini-Hochberg. There was no difference in ACE I/D genotype between groups. ACTN3 XX genotype tended to be underrepresented in rugby union backs (15.7%) compared with forwards (24.8%, P = 0.06). Interestingly, the 69 back three players (wings and full backs) in rugby union included only six XX genotype individuals (8.7%), with the R allele more common in the back three (68.8%) than controls (58.0%; χ2 = 6.672, P = 0.04; OR = 1.60) and forwards (47.5%; χ2 = 11.768, P = 0.01; OR = 2.00). Association of ACTN3 R577X with playing position in elite rugby union athletes suggests inherited fatigue resistance is more prevalent in forwards, while inherited sprint ability is more prevalent in backs, especially wings and full backs. These results also demonstrate the advantage of focusing genetic studies on a large cohort within a single sport, especially when intrasport positional differences exist, instead of combining several sports with varied demands and athlete characteristics.

Fat mass and obesity associated (FTO) gene influences skeletal muscle phenotypes in non-resistance trained males and elite rugby playing position

“…Description of all molecular procedures have previously been described in detail [22]. Briefly, blood (~70% of all samples), saliva (~25%) or buccal swab samples (~5%) were obtained via the following protocols.…”

“…As established previously [22], to compare genotype and allele frequencies within the RU group, athletes were allocated to subgroups; forwards (props, hookers, locks, flankers, number eights) and backs (scrum halves, fly halves, centres, wings, full backs). Also, due to diverse physiological demands within RU [33, 34], athletes were further divided into established positional groups according to their movement patterns [33]; front five (props, hookers, locks), back row (flankers, number eights), half backs (scrum halves, fly halves), back three (wings and full backs) and centres.…”

“…This lack of association was likely due to the considerable differences in physiological demand between the various athletic disciplines included, plus further variability in the standard of athlete. We have recently shown the ability of genetic research in a single sport with player roles that differ distinctly, namely rugby union (RU), to reveal context-specific competitive advantages provided by particular alleles [22]. Therefore, as RU includes athletes of remarkably distinct anthropometric and body composition phenotypes, elite RU provides a unique opportunity to investigate FTO in individuals at the extreme upper end of physical fitness [23].…”

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“…Moreover, despite intensive research, while there is only a little progress in the identification of genes that are locally or widely associated with athletic qualities [33] with the exception of variants in the genes ACTN3 and ACE [19,21,28]. The reason for this is as follows:…”

“…Angiotensin-converting enzyme gene (ACE) which had concluded that one of the polymorphic alleles of ACE gene is allele-I provides tolerance, and allele-D -speed-power qualities of athlete, on the basis of higher frequency of alleles in athletes, successful in their respective sports in relation to the control group [17]. However, in the future, a number of authors will find no differences in the frequency of occurrence of genotypes in athletes and people who are not involved in sports [18,19]. Nevertheless, differences will be appeared in the analysis of the study in athletes' genotypes, specializing in several sport fields [20].…”