Tauopathies may be further distinguished by the predominant isoform content of the tau inclusions: 4R tau (e.g., progressive supranuclear palsy, corticobasal degeneration, globular glial tauopathy), 3R tau aggregations (e.g., Pick disease), or mixed (e.g., AD) (see Figure 4). Here, MAPT is linked to progressive supranuclear palsy.