Highlights from the Functional Single Nucleotide Polymorphisms Associated with Human Muscle Size and Strength or FAMuSS Study

Abstract

The purpose of the Functional Single Nucleotide Polymorphisms Associated with Human Muscle Size and Strength study or FAMuSS was to identify genetic factors that dictated the response of health-related fitness phenotypes to resistance exercise training (RT). The phenotypes examined were baseline muscle strength and muscle, fat, and bone volume and their response to RT. FAMuSS participants were 1300 young (24 years), healthy men (42%) and women (58%) that were primarily of European-American descent. They were genotyped for ~500 polymorphisms and completed the Paffenbarger Physical Activity Questionnaire to assess energy expenditure and time spent in light, moderate, and vigorous intensity habitual physical activity and sitting. Subjects then performed a 12-week progressive, unilateral RT program of the nondominant arm with the dominant arm used as a comparison. Before and after RT, muscle strength was measured with the maximum voluntary contraction and one repetition maximum, while MRI measured muscle, fat, and bone volume. We will discuss the history of how FAMuSS originated, provide a brief overview of the FAMuSS methods, and summarize our major findings regarding genotype associations with muscle strength and size, body composition, cardiometabolic biomarkers, and physical activity.

A genetic variant in IL‐15Rα correlates with physical activity among European–American adults

“…Men homozygous for the A allele reported spending more time in light intensity physical activity than men homozygous for the C allele, explaining 5.8% of the variability in habitual physical activity; while these associations were not apparent in women. This finding is consistent with much of the work published by FAMuSS study investigators in that a persistent effect modifier of FAMuSS findings has been sex differences in the various phenotypes examined (Pescatello et al., ). Furthermore, they are consistent with the “Activity Genomic” literature that physical activity is a polygenetic trait such that there are many genes accounting for small effects (de Moor et al., , ).…”

“…The aim of this substudy was to determine whether IL‐15R α 1775 A>C associated with habitual physical activity in a large subsample of healthy European‐American adults from FAMuSS (Pescatello et al., ; Thompson et al., ). The most noteworthy finding was the IL‐15R α 1775 A>C made a small but meaningful contribution to the interindividual differences we observed in habitual physical activity that varied by sex and the intensity of physical activity performed.…”

“…IL15Ra 1775A>C meets these criteria. Therefore, the purpose of our study was to test the hypothesis that IL-15-Ra 1775 A>C would influence habitual physical activity in a large subsample of 532 young European-American adults from FAMuSS (Pescatello, Devaney, Hubal, Thompson, & Hoffman, 2013;Thompson et al, 2004).…”

The angiotensin-converting enzyme insertion/deletion polymorphism rs4340 associates with habitual physical activity among European American adults

“…The experimental design of FaMuSS has been described elsewhere, so only the methods related to this substudy are described (Pescatello et al. ).…”

Letter to the editor: A genetic-based algorithm for personalized resistance training

“…To better identify genetic contributions, larger, well-defined samples were needed, and some consortia were formed such as FAMuSS. Studies rely on these resources to obtain data related to the response to interventions related to exercise [18, 19]. Indeed, the possibility to identify genes and their allelic states that could determine which individuals would perform better in some sports disciplines brought the concept of genetic scores based on a personal genetic profile [20].…”