Blood Test for Suicide May Come From Stress Gene Defect

A gene tied to negative thoughts and impulses may lead to a blood test predicting suicide risk, according to researchers who said such a tool could help prevent a leading cause of death.


Scientists from Johns Hopkins University in Baltimore discovered that a mutation to a gene, called SKA2, appeared to prevent the brain from responding normally to stress hormones. An analysis of brain tissue from people who had killed themselves found depleted levels of SKA2.

The finding, published online today in the Journal of Psychiatry, adds to recent genetic discoveries in psychiatry that promise to advance treatment and diagnostics in the field. Suicide is the 10th-leading cause of death in the U.S., according to the Centers for Disease Control and Prevention. While there are known risk factors, such as mental illness, drug abuse or distressful life events, there is no consistent way to predict suicide, researchers said.

"We have found a gene that we think could be really important for consistently identifying a range of behaviors from suicidal thoughts to attempts to completions," Zachary Kaminsky, the lead study author and an assistant professor of psychiatry and behavioral sciences at the Johns Hopkins University School of Medicine, said in a statement. "With a test like ours, we may be able to stem suicide rates by identifying those people and intervening early enough to head off a catastrophe."

In a series of experiments, researchers focused on the SKA2 gene, first by looking at brain samples from mentally ill and healthy people. In addition to having reduced levels of SKA2, there were also higher levels of methyl chemicals in people who had died from suicide, the study found.
Stress Hormones

The SKA2 gene is in charge of regulating stress hormones, such as cortisol. If there isn't enough SKA2, the stress hormone receptor it brings into cells isn't able to suppress the release of cortisol, a chemical throughout the brain. Cortisol levels have been linked to suicide.

The study then tested blood samples of 325 participants and found a correlation between methylation increases at SKA2 in individuals with suicidal thoughts or attempts. With this finding, researchers devised a model analysis that predicted, with 80 percent accuracy, which of the participants were experiencing suicidal thoughts or had attempted suicide.

A simple blood test could greatly help doctors, in clinics or in emergency rooms, in their decisions on therapy or to prevent a tragedy, such as suicide-monitoring, restricting weapons and other lethal means patients might use to take their own lives. It could also be useful for the military when assessing soldiers as they return home from the battlefield, Kaminsky said.

New Findings
The findings are a direct result of new technologies that enable scientists to peer deeper into human DNA, identifying genes and genetic alterations responsible for variety of ailments, now including those as mysterious as mental illness.

Researchers had earlier reported identifying 128 genes in 108 locations in the human genome tied to schizophrenia. The findings may point the way to new therapies for the disorder, which has been treated for more than 50 years with drugs that have the same mechanism of action. The findings revealed genes in areas tied to learning, memory, brain signaling and the immune system.