New mitochondrial DNA biomarker could reveal Alzheimer's disease years before onset

The CSIC researchers demonstrated that a decrease in the content of mitochondrial DNA (mtDNA) in CSF may be a preclinical indicator for Alzheimer's disease; furthermore, there may be a directly causative relationship. The hypothesis is that decreased mtDNA levels in CSF reflect the diminished ability of mitochondria to power the brain's neurons, triggering their death. The decrease in the concentration of mtDNA precedes the appearance of well-known biochemical Alzheimer's biomarkers (the A?1-42, t-tau, and p-tau proteins), suggesting that the pathophysiological process of Alzheimer's disease starts earlier than previously thought and that mtDNA depletion may be one of the earliest predictors for the disease.