From war veterans to football players, motorcyclists to construction workers, the potential for brain damage exists in a variety of hobbies and professions, across many different modalities. Now researchers from the University of Illinois at Urbana-Champagne have discovered in a new study that one gene is responsible for determining if a person can ever fully recover from his or her traumatic brain injury (TBI).

Most TBI comes in the form of concussions, generally through blunt force trauma. According to the Centers for Disease Control and Prevention, the injuries are responsible for nearly a third (30.5 percent) of all injury-related deaths in the U.S. And while treatment for TBI isn’t always available, the present researchers believe their findings move science in the right direction, as the change in one gene — a difference known as polymorphism — correlated with greater cognitive performance.

Study leader Aron Barbey, together with his colleagues at the University of Illinois, collected data on 156 Vietnam War veterans. "We administered a large, cognitive battery of tests to investigate how they performed after their injury,” Barbey said in a statement. The team measured subjects’ IQ, the size of their brain injury, and controlled for their intelligence levels prior to sustaining the injury. They also “had a team of neurologists who helped characterize the nature and scope of the patients' brain injuries."

The team took blood samples in order to conduct a genetic analysis, focusing specifically on one gene, known as BDNF (brain-derived neurotrophic factor). It was on this gene, the team found, that one “letter” difference swung the entire findings one way or another. Among BDNF’s responsibilities is aiding in neurogenesis; that is, the production of new neurons. As the vets had sustained penetrating injuries to their prefrontal cortexes — an area responsible for planning, complex thought, and self-restraint — examining BDNF’s effects was believed to weigh heavily on the end results.

Ultimately, researchers found that a change in BDNF alters the protein associated with it. Since people each carry two versions of specific genes, one from each parent, the team found that when the amino acid methionine (Met) was incorporated at a site rather than valine (Val), intellect recovery tended to accelerate. The mere presence of Met was enough to produce the same effects. In other words, subjects with either Met/Met or Val/Val gene pairs did far better on their cognitive tests than did Val/Val subjects — by about eight IQ points overall.

"The effects of this difference were large,” Barbey said, “very large.” What’s more, the Val/Val subjects lacked "specific competencies for intelligence like verbal comprehension, perceptual organization, working memory, and processing speed.”

With this research, Barbey and his team hope to pave new avenues for investigating gene signaling. The past several years have seen great leaps forward in scientists’ abilities to manipulate specific genes. If they can transfer the ability to TBI victims, those who have difficulty with recovery may one be able to reclaim their lives.

 

Source: Barbey A, Colom R, Paul E, et al. Preservation of General Intelligence following Traumatic Brain Injury: Contributions of the Met66 Brain-Derived Neurotrophic Factor. PLoS ONE. 2014.