Indeed, several large cohort-based genome-wide association studies (GWASs) in recent years have identified signals which shed new light on our understanding of MDD, for example, implicating the presynaptic protein piccolo and alpha-1 subunit of a voltage-dependent calcium channel in the pathogenesis of MDD4,5 and shared genetic risk for MDD, bipolar disorder and schizophrenia6,7. The gene discussed is PSMA6; the disease is major depressive disorder.