MAPT and tauopathy: Sporadic tauopathies are classified based on the pattern of morphological distribution of the inclusions, what types of cells accumulate tau, and the biochemical composition of tau inclusions, namely predominance of three microtubule-binding repeat (3R) tau, four microtubule-binding repeat (4R) tau or a combination of both (3R/4R) [3] (Fig. 1).