Multiple genes encoded by chromosome 13 have been suggested to contribute to schizophrenia susceptibility, including DAOA [42], 5-HTR2A [43], KPNA3 and KPNB3 [44], ESD [45], ATXN8OS [46], KFL5 [47], EFNB2 [48], and PCDH8 [49]. This evidence concerns the gene PCDH8 and schizophrenia.