Examples of diagnostic-biased genes include GRIA4 (glutamate receptor, inotropic, AMPA4) and ASTN2 (astrotactin 2) (Figure 2), both of these genes have been previously implicated in schizophrenia (Makino et al., 2003; Vrijenhoek et al., 2008; Wang et al., 2010). This evidence concerns the gene ASTN2 and schizophrenia.