Despite significant advances in treatment, sports-related concussion continues to plague athletes. Part of the reason for this is that the biological basis of concussion is poorly understood. Genetics play a key role in the biology underlying concussion. In this study, investigators performed the first genome-wide association study for concussion. Investigators screened the entire genome for genetic differences associated with the injury in two large cohorts. DNA polymorphisms in the PLXNA4 and SPATA5 genes were found to be associated with concussion. PLXNA4 encodes a type of nerve cell receptor whose role is to steer nerve growth. For SPATA5, previous work found that individuals carrying two strong, deleterious mutations of this gene produce symptoms that are similar to concussion like intellectual disability, hearing loss and vision impairment. This study found that these genetic markers identified individuals with about a three-fold increased risk for concussion. This information might lead to improved prevention and treatment for concussion, help inform return-to-play guidelines, and perhaps direct an athlete’s choice of sport.