In the Yale-Penn participants of African descent, we identified the HGF gene as an interactive locus with polysubstance dependence in the context of SI. Although we could only conduct limited follow-up analyses due to the weakness of the statistical evidence, we found nominally significant association of HGF gene with the exposure to life-threatening traumatic events in UK Biobank. A recent GEWIS analysis in UK Biobank tested the interaction between traumatic experiences and genetic variation with respect to suicidality, identifying loci involved in brain extracellular matrix biology and synaptic plasticity50. The identification of the HGF locus appears to be in line with these independent results. Indeed, the protein product of the HGF gene is a neurotrophic growth factor that exerts pleiotropic effects on the central nervous system51. Further studies will be needed to understand the role of the HGF locus in gene-by-environment interactions related to suicidality.
