MAPT and Parkinson disease: Other genes are linked to Parkinsonism in an autosomal dominant fashion and are responsible for early onset forms of PD (α-synuclein duplications or triplications, some families with mutated α-synuclein) as well as the more common late onset forms of Parkinsonism (α-synuclein mutants, tau, LRRK2, VPS35, or EIF4G1; Houlden and Singleton, 2012).