Schizophrenia Daily News Blog

Mitochondrial DNA is abnormal in bipolar disorder and schizophrenia

A New Study suggests that Maintenance of mitochondrial DNA is abnormal in bipolar disorder and schizophrenia

A new resesarch report out of Japan has reported that there are unusual mitochondrial DNA deletions in the brains of patients with bipolar disorder and schizophrenia. "Several clinical, genetic and neuroimaging studies implicate mitochondrial dysfunction in the pathophysiology of bipolar disorder and schizophrenia.

The report stated that:

"A lack of normal age-related accumulation of this deletion in schizophrenia and increased occurrence of the common deletion in bipolar disorder have been reported," wrote C. Kakiuchi and colleagues, RIKEN.

"However, even in the affected bipolar samples, the levels of common deletion were relatively small, indicating that the common deletion did not play a pathophysiological role in respiratory function. We hypothesized that accumulation of multiple mtDNA deletions, rather than the common deletion alone, is involved in the pathophysiology of these two major mental disorders."

"We observed no association between mtDNA deletions and the two major mental disorders in the frontal cortex, which did not support our hypothesis. We did, however, make the following observations, although they were not significant after Bonferroni correction: (1) the ratio of mtDNA to nuclear DNA was significantly higher in female patients with schizophrenia than in control females (p=.040), and (2) in bipolar disorder, the relative amount of mtDNA decreased with age (p=.016)."

They concluded, "Our results suggest that abnormalities in the system maintaining replication of mtDNA may underlie bipolar disorder and schizophrenia."

Source: (Quantitative analysis of mitochondrial DNA deletions in the brains of patients with bipolar disorder and schizophrenia. Int J Neuropsychopharmacol, 2005;8(4):515-522).