Additionally, as one would predict biologically, evidence for epistatic interaction is emerging: three-way interaction between specific SNPs in CIT, DISC1 and NDEL1 has been reported for schizophrenia (Nicodemus et al., 2010); there is strong statistical interplay between the HEP3 haplotype and NDE1 in the Finnish population (Hennah et al., 2007) and haplotypes of NDE1 and NDEL1 show association that is dependent on the Ser or Cys variant at position 704 in DISC1 (Burdick et al., 2008). This evidence concerns the gene CIT and schizophrenia.