MAPT and argyrophilic grain disease: Primary tauopathies feature tau deposits as the predominant pathological signature and include progressive supranuclear palsy (PSP), corticobasal degeneration (CBD), frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17), Pick’s disease (PiD), chronic traumatic encephalopathy (CTE) and argyrophilic grain disease (AGD) [1, 2].