However, several studies have demonstrated increasing evidence of tau pathology in PD brain.11,13–16 Genome-wide association studies (GWAS) of the sporadic form of PD11,17 have identified MAPT, encoding the microtubule-associated protein tau, as being associated with an increased risk of disease.18 Whether tau pathology precedes Lewy pathology and the role that it plays in nigrostriatal degeneration is an important question that has not been addressed to date. Here, MAPT is linked to Parkinson disease.