While both α-synuclein and tau accumulation are often a neuropathological feature of clinically diagnosed PD patients following post-mortem examination, a recent study demonstrated that adenoviral over-expression of tau, but not α-synuclein, was sufficient to promote dopaminergic neuronal loss and impair rotational behavior in otherwise normal rats, further supporting an important role for tau in the pathogenesis of PD [16]. The gene discussed is MAPT; the disease is Parkinson disease.