Scientists at Boston University have found a gene that could help predict the risk of suicide and PTSD.

As they describe in their recent Molecular Psychiatry paper, the gene SKA2 tends to be “switched off” in the brains of people who die from suicide. The risk of suicide for Iraq and Afghanistan veterans is currently estimated to be 41 to 61 percent higher than in the general population.

A 2014 study in the Journal of Psychiatry was the first to make the link between suicide risk and SKA2 but only analyzed post-mortem brains. The Boston University study went a step further by looking at the status of SKA2 in the brains of living individuals thinking suicidal thoughts.

Using neuroimaging data from the Translational Research Center for TBI and Stress Disorders database, a compendium of health data on trauma-exposed Iraq and Afghanistan war veterans, the researchers examined the genes of 145 individuals for the presence of methyl groups — tiny groups of carbon and hydrogen molecules tagged to specific locations on the gene.

Methylation, as the tagging process is called, is one way the body activates or deactivates a gene. The researchers found that people with more methylation on the SKA2 gene tended to have more severe PTSD as well as less brain tissue in certain areas.

It isn’t clear yet what effect turning off SKA2 has on the brain, but some studies have suggested that it’s involved in a hormonal system linked to regulating stress.

While suicide and PTSD risk are far too complex to assess by looking at only one gene, future studies on SKA2 could lead to better treatments, such as drugs that can reverse its methylation or enhance its activity.

And veterans won’t be the only people who might benefit from such research — suicide and PTSD, after all, affect many others as well.