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

Abstract

Background FTO gene variants have been associated with obesity phenotypes in sedentary and obese populations, but rarely with skeletal muscle and elite athlete phenotypes.MethodsIn 1089 participants, comprising 530 elite rugby athletes and 559 non-athletes, DNA was collected and genotyped for the FTO rs9939609 variant using real-time PCR. In a subgroup of non-resistance trained individuals (NT; n = 120), we also assessed structural and functional skeletal muscle phenotypes using dual energy x-ray absorptiometry, ultrasound and isokinetic dynamometry. In a subgroup of rugby athletes (n = 77), we assessed muscle power during a countermovement jump.ResultsIn NT, TT genotype and T allele carriers had greater total body (4.8% and 4.1%) and total appendicular lean mass (LM; 3.0% and 2.1%) compared to AA genotype, with greater arm LM (0.8%) in T allele carriers and leg LM (2.1%) for TT, compared to AA genotype. Furthermore, the T allele was more common (94%) in selected elite rugby union athletes (back three and centre players) who are most reliant on LM rather than total body mass for success, compared to other rugby athletes (82%; P = 0.01, OR = 3.34) and controls (84%; P = 0.03, OR = 2.88). Accordingly, these athletes had greater peak power relative to body mass than other rugby athletes (14%; P = 2 x 10-6).ConclusionCollectively, these results suggest that the T allele is associated with increased LM and elite athletic success. This has implications for athletic populations, as well as conditions characterised by low LM such as sarcopenia and cachexia.

Prevalence and association of single nucleotide polymorphisms with sarcopenia in older women depends on definition

“…There was an association between FTO rs9939609 AA and lean body mass; however, that association disappeared when controlling for fat mass 41,47 . Recent studies have reported over-representation of FTO rs9939609 AA genotypes in heavier athletes 48,49 , however, none has investigated how the body mass and muscle mass are affected by this genotype in those athletic populations. We previously demonstrated that the T-allele is associated with higher appendicular and arm lean mass in untrained young men 49 .…”

“…Recent studies have reported over-representation of FTO rs9939609 AA genotypes in heavier athletes 48,49 , however, none has investigated how the body mass and muscle mass are affected by this genotype in those athletic populations. We previously demonstrated that the T-allele is associated with higher appendicular and arm lean mass in untrained young men 49 . It therefore appears that FTO AA-genotype individuals have lower skeletal muscle mass and are at higher risk of sarcopenia.…”

Replication of FTO Gene associated with lean mass in a Meta-Analysis of Genome-Wide Association Studies

“…Loos et al have shown that homozygous Fto −/− mice have postnatal growth retardation, obviously decreasing in adipose tissue, and LBM 40 . According to the studies of athletes the T-allele of FTO gene rs9939609 is associated with increased lean mass for the elite rugby athletes, and for combat sports athletes the A-allele is related with decreased slow-twitch muscle fibers 29,42 . AMPK (AMP-activated protein kinase) is an essential part of skeletal muscle lipid metabolism and is the major cellular energy sensor.…”

“…But the exact biological functions of this gene are unknown yet. In recent researches, FTO gene is proved the association with lean mass 22,23,[26][27][28][29][30][31] . Zillikens et al reported a series of SNPs of FTO associated with LBM and appendicular lean mass (ALM) 30 .…”

COL5A1 gene variants previously associated with reduced soft tissue injury risk are associated with elite athlete status in rugby

“…As part of the ongoing RugbyGene project [ 12 , 13 , 34 ], a total of 1105 individuals were recruited and gave written informed consent to participate in the present study. An a priori calculation for 80% power to detect a small effect size (w) of 0.1 required a sample of >785 participants.…”