PIN1 and Alzheimer disease: It is significant that, during the development of AD, PIN1 function is downregulated and/or inhibited,27, 57, 58, 59, 60, 61 leading to elevated levels of the cis pThr 668-Pro motif,44 and it has been shown that deletion of PIN1 in mice causes tau and Aβ-related pathologies and neurodegeneration in an age-related manner.44, 62