Schizophrenia [MIM 181500] is a complex brain disorder characterized by disturbances in multiple domains of brain function, including cognitive, emotional, and perceptual processes [30]. Evidence for schizophrenia as a neurodevelopment disorder began more than 30 years ago [31] and has been accepted commonly [32]. It is intriguing to note that the 8 pathways discovered by SSEA in both the EA and AA samples included 4 pathways important for neurodevelopment and neuronal functioning, such as axon guidance pathway, neuroactive ligand-receptor interaction pathway, long-term depression pathway and long-term potentiation pathway. Axon guidance pathway and neuroactive ligand-receptor interaction pathway are directly related to neuroplasticity and neuropathology, and thus are important to the genetic mechanism of schizophrenia [33]. Long-term depression pathway and long-term potentiation pathway were reported to be important for synaptic plasticity development and related to schizophrenia [34,35]. Besides, axon guidance pathway, long-term depression pathway and long-term potentiation pathway were reported in a recent study where pathways were overrepresented by genes disrupted by copy number variants in schizophrenia cases [36]. Genes in the focal adhesion pathway are principally involved in the biological processes
