MAPT and corticobasal syndrome: Parkinsonism may be seen with any of the mutations with a variable phenotype, sometimes very similar to idiopathic Parkinson's disease (in MAPT mutations), in other cases, a corticobasal syndrome (with GRN or, less commonly, MAPT mutations), and more rarely a progressive supranuclear palsy syndrome (with MAPT mutations) (Rohrer and Warren, 2011).