MAPT and Alzheimer disease: PSP was shown to have shared polygenic heritability with Parkinson's disease and ALS, and most of the corresponding genes were clustered around chromosome 17.[99,100] Interestingly, AD, primary age related tauopathy (PART), and aging-related tau astrogliopathy (ARTAG) are the predominant sporadic tauopathies, in which oligodendrocytes serve as targets for seeding and spreading pathologic tau proteins in the white matter.[101] Given that the human retina lacks oligodendrocytes, these cells may not be a component in the pathogenesis of tauopathies in the eye.