Synaptic development and functionality have been considered as fundamental mechanisms underlying a range of neuropsychiatric disorders, including schizophrenia. Emerging evidence from biological and clinical studies implicates mutations in the Disrupted-in-Schizophrenia-1 (DISC1) gene in the pathogenesis of schizophrenia. In this study, genetic interactions among a select set of risk factor genes are examined using the unique model system: neuromuscular junctions (NMJs) in Drosophila. We found t