A small number of single-gene CNVs have been associated with schizophrenia, but the only ones to be definitively implicated are deletions of NRXN1 (Kirov et al., 2008; Rees et al., 2014b), which encodes the presynaptic cell adhesion protein neurexin 1. This evidence concerns the gene NRXN1 and schizophrenia.