MAPT and Alzheimer disease: Based on the predominant tau isoform found in the aggregates, tauopathies are pathologically classified into three main categories: 3R tauopathies (frontotemporal dementia (FTD)), 4R tauopathies (progressive supranuclear palsy (PSP), corticobasal degeneration (CBD), argyrophilic grain disease (AGD), and globular glial tauopathy (GGT)), and 3R/4R tauopathies (Alzheimer’s disease (AD), chronic traumatic encephalopathy (CTE)) and primary age-related tauopathy (PART) [19].