The observation that DICER1 was significantly increased in BP neurons suggests a potential mechanism to explain the growing consensus that multiple genes may be misregulated in BP. As microRNAs alter the translation of as many as 70% of all human genes,66 alterations in microRNA production would affect multiple gene products. MicroRNA levels are altered in postmortem brain tissue of BP patients,67,68 and are sensitive to lithium.69, 70, 71, 72 MicroRNAs have critical roles in neural development,73, 74, 75 as well as in the adult brain;76 misregulation would therefore be expected to produce both short- and longer term affects on CNS development and function.
