Previous studies mainly focused on five genes located in the 1.5 Mb region, which confer risk of schizophrenia based on studies of human genetics and using animal models.4, 9, 10, 11, 12, 13 The five genes are: COMT (encoding a central enzyme in monoamine catabolism), PRODH (encoding an enzyme required for proline metabolism), TBX1 (encoding a transcription factor involved in the embryonic development of multiple tissues and organs), ZDHHC8 (encoding a palmitoyl transferase enzyme) and DGCR8 (encoding a key regulator of microRNA synthesis). This evidence concerns the gene DGCR8 and schizophrenia.