MAPT and neurodegenerative disease: Harmful metal exposure has for a long time been suspected to contribute to neurodegenerative diseases.[1, 8, 9, 65, 66, 67, 68, 69] Thus, both endogenous metals such as Cu, Fe, and Zn and numerous exogenous metals have been investigated in relation to AD, either by measuring metal concentrations in blood and brains of AD patients,[8, 12, 70] or by in vitro studies of metal ion interactions with disease‐related molecules such as Aβ and tau.[40, 42, 71, 72, 73, 74, 75]