Finally, although ET itself is not a tauopathy (i.e., a class of neurodegenerative disorders whose main features are accumulation of hyperphosphorylated tau protein), ET may predispose individuals to accumulate more widespread cellular tau aggregates, and thus tau could play a central role in the cognitive impairment that can accompany ET, as some evidence would indicate.[54,55]. Here, MAPT is linked to essential thrombocythemia.