Led by Zachary Kaminsky of the Johns Hopkins University School of Medicine in Baltimore, Maryland, the study began with a genome-wide scan for methylation changes in neurons and glial cells in post-mortem brains to identify genes associated with suicide. The search linked epigenetic and genetic changes in a single nucleotide polymorphism (SNP), rs7208505, within the SKA2 gene to a higher probability of suicidal ideation. SKA2 gene expression was significantly lower in suicide decedents, an effect linked to variations in this SNP.
Changes in SKA2 expression were also linked to suicidal behaviors in blood tests on three live cohorts. An assessment of stress—as measured by salivary cortisol levels—suggested that the gene may act to suppress cortisol and mediate stress responses. The correlation of SKA2 with anxiety and stress could potentially “explain about 80 percent of suicidal behavior, and progression from suicidal ideation to suicide attempts,” the authors wrote in their paper.
“SKA2 has been implicated as important for the normal function of stress receptors,” Kaminsky told Popular Science. “It chaperones them, and it goes up when glucocorticoid binds to these receptors, which happens when you get stressed out.”
Previous searches for blood biomarkers of suicidal thoughts have yielded other potential genes. The Scientist reported last year that researchers had identified six candidate biomarkers for suicidal thoughts, in genes related to stress and cell death. Although a simple blood test to predict an individual’s potential for suicidal thoughts could benefit the community, biomarkers for self-harm have yet to reach clinical trials.