NRG1 and schizophrenia: Although the overall results generally supported the association between NRG1 rs6994992 and schizophrenia, there has also been evidence suggested an ethnic difference in the relationship between NRG1 rs6994992 and schizophrenia, with the association mainly being present in the European populations (Li et al., 2006; Mostaid et al., 2016; Jagannath et al., 2017).