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 this disorder. Aim To identify RNA transcripts that are up- or down-regulated in the frontal 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 differentially 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 protein and components of the NF-kappaB transcription factor complex are significantly increased in individuals with bipolar disorder compared with unaffected controls. Increased levels of expression of these RNA transcripts were also detected in the brains of some individuals with schizophrenia and unipolar depression. Conclusion The SAGE technique offers promise for the characterisation of complex human brain diseases.