NRG1 and schizophrenia: As the type-1 NRG1 variant display marked mRNA increase in patients' postmortem brain and single nucleotide polymorphisms (SNPs) of its corresponding genome locus are implicated in genetic vulnerability to schizophrenia [18], [19], we have established mouse transgenic lines carrying the transgene of mouse type-1 NRG1 cDNA and examined whether NRG1 hypermorphic mice, as opposed to NRG1 hypomorphic mice, are an appropriate animal model for schizophrenia.