MAPT and synucleinopathy: Third, although mutations in MAPT (microtubule-associated protein tau, or often referred to simply as tau) lead to a disorder that can closely clinically resemble idiopathic Parkinson disease, the majority have a dementing syndrome that is clearly different from Parkinson disease; however, the MAPT/tau haplotype shows an association with disease (see below) strongly suggesting that the pathogenic cascades in the tauopathies must be related to those in the synucleinopathies.