Genetic Predisposition Score for Hand Grip Strength in the General Population

Abstract

Genetic profile analyses have been presented to predict elite athlete status. Athletes however represent subjects after a long trajectory of specific genotype*training interaction. PURPOSE: This study aims to test the predictive value of a genetic predisposition score for a general strength test (hand grip) in a non-athlete population. METHODS: 18 gene variants in 12 genes (ACVR2B, FST, CNTF(R), GR, IL6, IL15RA, VDR, ACTN3, IGF2, PPP3R1), previously associated with a muscle mass or strength phenotype were analyzed in an 'increasing allele' approach. A genetic predisposition score was determined, counting each increasing allele as an additional unit (e.g. ACTN3 577 RR= 2), which assumes equal additive effects for all variants. Alternatively, a dominant model was tested (e.g. XX=0, XR or RR=1). Regression analysis tested the significance of the slope. Full genotyping data and hand grip measurements (JAMAR) were available in 208 males of the Leuven Genes for Muscular Strength Study (23.7±4.2 yr) and 97 males and 87 females of the Flanders Longitudinal Offspring study (47.0±0.7 and 40.5±1.1 yr) and 75 seniors (46% females; 66.1±4.0 yr).FigureRESULTS: In the male sample, additive predisposition score did not significantly contribute to hand grip. However, for the dominant predisposition score (gpsd), each additional heterozygous or homozygous genotype increased handgrip by 0.77 kg (SE 0.29, p=0.008), after age was included as a covariate (partial r2 for gpsd=.015). In females, slopes were not different from zero. CONCLUSIONS: A dominance genetic predisposition score based on 18 gene variants predicted an increase in hand grip strength of 0.77 kg per additional increasing genotype in males; however the amount of explained variance is small.