Parkinson's disease (PD), a disorder of unknown etiology, is associated with the degeneration of dopaminergic neurons in nigro-striatal pathways. MPTP, a meperidine analog, causes parkinsonism in human and nonhuman primates. MPP+, the active metabolite of MPTP, inhibits the activity of respiratory chain complex I. In patients with PD, a reduced complex I activity was found in substantia nigra, skeletal muscle, and platelets. Because complex I is partially encoded by the mitochondrial genome, several studies have searched for mitochondrial (mt) DNA abnormalities in patients with PD. Our aim was to answer the following questions: (1) are there some abnormalities of mtDNA in PD? (2) if there are some, what are these abnormalities? and (3) what is the pathogenic role of these abnormalities?
Methods: The literature review was performed using Medline [National Library of Medicine, Washington] and Current Contents [Institute for Scientific Information, Philadelphia] databases. Periods screened were 1966-March, 1998 (Medline) and March 17, 1997-March 9, 1998 (Current Contents). Keywords were: "Parkinson" or "Parkinson's", and "mitochondrial DNA" or "mtDNA". We limited our research to articles in English and French.
Results: Medline search provided 59 articles. Current Contents search provided 22 articles. Twelve articles were found in both databases. Thirty-eight of the 69 articles were either reviews about mitochondrial diseases (19 articles) or original articles not related to mtDNA (19 articles). Our final selection included the remaining 31 articles.