MAPT and neurodegenerative disease: A postulated concept about tauopathy is that the disease phenotypes are caused by loss of tau function due to hyperphosphorylation and subsequent tangle formation.49 However, recent studies have shown that loss of tau function is an unlikely cause of neurodegeneration.50, 51, 52 Morris et al.36 have proposed a tempting concept concerning hyperphosphorylated tau; they speculated that the tau protein in AD is hyperphosphorylated and released from its binding partner to counteract neuronal dysfunction in neurodegenerative diseases such as AD.