Our results indicate that vCSF ccf-mtDNA is significantly reduced in post-mortem PMS cases compared to controls which, when taken into context with observations in both Parkinson's disease (PD) (Pyle et al., 2015a) and Alzheimer's disease (AD) (Podlesniy et al., 2013), supports our hypothesis that ccf-mtDNA may be an component of neurodegeneration. The gene discussed is PITX1; the disease is Alzheimer disease.