MAPT and Parkinson disease: Moreover, specifically knocking down tau in the β-islet induced elevated insulin secretion, indicating the importance of pancreatic tau on metabolic traits.1 Of note, pancreatic tau is significantly up-regulated not only in T2DM but also in neurodegenerative diseases like Alzheimer’s disease (AD), dementia with Lewy bodies, Parkinson’s disease, and incidental Lewy body disease.3 This raises intriguing questions.