PTEN and Parkinson disease: The list includes TP53 (62) that contributes to the apoptotic deterioration taking place in PD, PTEN (63) that has been linked to PD via DNA damage and DNA repair machinery, SMAD1 (64) is an important regulator required for neurite growth, EZH2 (65) is a lysine methyltransferase component of polycomb repressive complex 2 that has been associated with PD and BCL2 (66) is required for proper development of the dopaminergic system and has been implicated in the pathogenesis of PD.