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. Here, MAPT is linked to Parkinson disease.