Meanwhile, the Notch4 locus has been identified as a candidate susceptibility gene for schizophrenia (Stefansson et al., 2009), and the mRNA level of Notch1 is differentially expressed in parvalbumin-immunoreactive neurons in subjects with schizophrenia (Pietersen et al., 2014). The gene discussed is PVALB; the disease is schizophrenia.