NRG1 and schizophrenia: Moreover, putative loss of function variants of APH1B, a crucial component of the γ-secretase complex, were found to aggregate with NRG1 risk alleles in schizophrenia patients (Hatzimanolis et al., 2013) and Aph1b-loss of function mutations in rodents display behavioural phenotypes that are relevant for schizophrenia (Coolen et al., 2005, 2006; Dejaegere et al., 2008).