[Genetics and epigenetics of suicidal behaviors]

With more than 10 000 deaths each year in France, suicide is a major public health problem. Despite many known risk factors, suicide prediction remains extremely difficult in daily clinical practice. The identification of biomarkers, including genetic and epigenetic factors, is needed in suicidology in order to better understand pathophysiology of such behaviors and to improve the screening of individuals at high suicidal risk. Numerous studies have reported candidate genes involved in serotonergic system, HPA axis and neurotrophic system. Moreover, an interaction between genetic factors and environment is now admitted, facilitating emergence of a psychobiological vulnerability leading to the suicidal act. For instance, polymorphism of the serotonin transporter (5-HTTLPR) as well as its interaction with early life events (childhood abuse) are involved in suicidality in adulthood. Unfortunately pangenomic studies are not conclusive yet. Beyond serotonergic genes, the SKA-2 gene, which is involved in stress response, deserves more attention. SKA-2 genic expression and methylation level have been associated with the suicidal act. In the future, the combination of clinical, biological and genetic risk factors will probably improve detection of suicide risk.