CAN GENETIC TESTING BE USED TO PREDICT SPORTS PERFORMANCE AND INJURIES?
Genetic loci have been associated with sports performance and injuries. Physical endurance, strength, and other building blocks of athleticism are complex traits to which genetic loci have been associated. A gene that directly affects contractile muscle, alpha-actinin-3 (ACTN3), may affect strength, and variants in this gene have been associated with sprinters.
Genes involved in energy utilization and hypoxia (i.e., the lack of oxygen) have been shown to be associated with physical endurance. Many of them affect metabolic and mitochondrial function. These findings are not unexpected, given that mitochondria are involved in energy utilization and production. Examples of “endurance genes” include the PPAR-delta gene, which encodes a key regulator involved in energy utilization in which a variant (294T/C) has been associated with endurance; GYS1, which gives rise to a skeletal muscle glycogen synthase; and the beta2-adrenergic receptor gene. Similarly, variants in genes associated with hypoxia, a response to low oxygen, have been associated with endurance as well. Presumably, these variants affect efficient energy utilization and oxygen consumption in muscles subjected to long periods of use.
Genetic traits also have been associated with sports injuries. Tendon disorders have been associated with blood groups and collagen genes (a structural component of tendons), and collagen variants have been associated with propensities for ligament tears. Individuals at risk for cardiomyopathy can potentially die from physical exertion—indeed, in a high profile case, a rising star for the Boston Celtics, Reggie Lewis, died during practice and was diagnosed with hypertrophic cardiomyopathy, a disease known to have a genetic basis. Recently, concerns have been raised about head blows in football and boxing as causes for Alzheimer’s and Parkinson’s diseases. The advantages of screening for those at risk for such conditions seems obvious; those at risk for injury or death might choose not to pursue such recreational or career activities, or they might modify their training to minimize their risk. Many individuals who desire to pursue these activities, however, may opt out of testing for fear they could not then pursue them.