ERBB4 and schizophrenia: Aberrant activation of HER4 is associated with neurological diseases including amyotrophic lateral sclerosis (ALS), schizophrenia, and other psychological disorders, where inhibitory missense mutations in HER4, and either increased or decreased levels of the HER4 ligand NRG1, can lead to various disease phenotypes (Mei and Nave, 2014; Takahashi et al., 2013; Song et al., 2012).