Collagen gene sequence variants in exercise-related traits

Collagens are major structural proteins of tendons, ligaments and other components of musculoskeletal tissues. Rare mutations in many of the genes, which encode for the collagen α-chains, result in serious musculoskeletal disorders, highlighting the importance of this protein family in the normal structure and function of musculoskeletal tissues. Since these rare mutations cause severe disorders, it has been proposed that a lack of biological redundancy exists within the collagen fibril, and that collagen-encoding genes are therefore ideal candidates for association with less severe exercise-related traits. This review identifies a number of collagen gene variants which are associated with various exercise-related traits. Based on the evidence outlined in this review, we propose that a general genetic continuum exists for collagen genes and their associated traits. At one end of this general continuum model, a single mutation within one or more collagen genes will result in severe Mendelian disorders. At the other end of the continuum, functional variants within these collagen genes collectively contribute to the aetiology of anomalous multifactorial connective tissue traits, which arise as a result of the interaction of genetic and non-genetic factors which modulate physiological responses to environmental stimuli.