Mitochondrial DNA allelic substitutions in Parkinson’s disease

Mitochondrial DNA (mtDNA) damage is considered as a possible primary cause of Parkinson’s disease (PD). To explore the issue, mtDNA sequences from whole blood were analyzed in PD patients and controls using a resequencing chip and allelic substitutions were estimated for each nucleotide position (np) along the entire mtDNA sequence. Overall, 58 np showed a different allelic distribution in the two groups; of these, 81% showed an increase of non-reference alleles in PD patients, similar to findings reported in patients with Alzheimer’s disease, albeit in reduced proportion. These results suggest that age-related neurodegenerative diseases could share a mechanism involving mtDNA. This study included a total of 15 AD patients and 15 age-matched controls from the Report-AGE Database Sample Resource, the institutional database of INRCA (Italian National Research Center on Aging). Data acquisition was performed using the Affymetrix Genechip Command Console (AGCC) software and data analysis was carried out with GSEQ 4.1. The output files used for the study were Single Nucleotide Polymorphism (SNP) View and Probe Intensity files. Patient characteristics: 1) Locomotion mode: 0=Walk without aid 1=Walk with aid 2=Wheelchair 3=Bedridden 2) ADL Hierarchy scale: 0=Independent 1=Supervision 2=Limited 3=Extensive 4=Maximal 5=Dependent 6=Total dependence