INCREASED LEVELS OF A MITOCHONDRIAL-DNA DELETION IN THE BRAIN OF PATIENTS WITH BIPOLAR DISORDER

Mutations in mitochondrial DNA (mtDNA) have been implicated in the pat hophysiology of affective disorders, To examine possible pathophysiolo gical significance of mtDNA deletions in bipolar disorder, the concent ration of the 4977-base-pair deletion in mtDNA in the autopsied brains of 7 patients with bipolar disorder, 9 suicide victims, and 9 control s was examined using a quantitative polymerase chain reaction method. The ratio of deleted to wild-type mtDNA in cerebral cortex was signifi cantly higher in patients with bipolar disorder [0.23 +/- 0.18 (mean /- SD)%] compared with that in age-matched controls (0.06 +/- 0.07%, p < 0.05). This result supports a hypothesis that mtDNA deletions may p lay a role in the pathophysiology of bipolar disorder. (C) 1997 Societ y of Biological Psychiatry.