NRG1 and schizophrenia: Another recent study has shown that microsatellite repeats in intron 1 of the gene encoding neuregulin 1 (NRG1), a putative schizophrenia susceptibility gene regulating the excitatory-inhibitory balance, are associated with an increase in NRG1 transcripts in the prefrontal cortex, suggesting that this region could function as a transcriptional enhancer.