Serial analysis of gene expression in the frontal cortex of patients with bipolar disorder

Background Bipolar disorder is a serious brain disease affecting more than a million individuals living in the USA. Epidemiological studies indicate a role for both genetic and environmental factors in the pathogenesis of thi s disorder. Aim To identify RNA transcripts that are up- or down-regulated in the front al cortex regions of individuals with bipolar disorder. Method Serial analysis of gene expression (SAGE) and reverse transcriptase- polymerase chain reaction were used to identify RNA transcripts which are d ifferentially expressed in the frontal cortex of brains obtained postmortem from individuals with bipolar disorder compared with other psychiatric and control conditions. Results Levels of RNA transcripts encoding the serotonin transporter protei n and components of the NF-kappaB transcription factor complex are signific antly increased in individuals with bipolar disorder compared with unaffect ed controls. Increased levels of expression of these RNA transcripts were a lso detected in the brains of some individuals with schizophrenia and unipo lar depression. Conclusion The SAGE technique offers promise for the characterisation of co mplex human brain diseases.