This study aimed to fill these central knowledge gaps by investigating neuroinflammation, brain tau accumulation and dementia risk in 36 newly-diagnosed PD cases and 20 age-matched controls using PET neuroimaging in a 3-year longitudinal study (NEuroinflammation and Tau aggregation in Parkinson’s Disease Dementia, NET-PDD). The gene discussed is MAPT; the disease is dementia.