NRG1 and schizophrenia: The direct and chronic disturbance of NRG1/ErbB4 signal transmission, such as the mutation of NRG1 or ErbB4 gene in some schizophrenia patients (Walss-Bass et al., 2006), can lead to the abnormality of glutamatergic synapses and nerve fibers, thus leading to developmental and functional abnormalities.