Accumulation of mitochondrial DNA deletions within dopaminergic neurons triggers neuroprotective mechanisms.

Acquired alterations in mitochondrial DNA are believed to play a pathogenic role in Parkinson's disease. In particular, accumulation of mitochondrial DNA deletions has been observed in substantia nigra pars compacta dopaminergic neurons from patients with Parkinson's disease and aged individuals. Also, mutations in mitochondrial DNA polymerase gamma result in multiple mitochondrial DNA deletions that can be associated with levodopa-responsive parkinsonism and severe substantia nigra pars compacta dopaminergic neurodegeneration.