Several schizophrenia-associated genes were down-regulated in the hippocampus of Dgcr8+/- mice (Ouchi et al., 2013), including the insulin-like growth factor 2 (IGF2), which was recently found to play a crucial role in hippocampal functions such as memory consolidation and fear extinction (Agis-Balboa et al., 2011; Chen et al., 2011a). This evidence concerns the gene IGF2 and schizophrenia.