ATP13A2 and Parkinson disease: Perhaps the most direct evidence to date linking lysosomal impairments to PD is the demonstration that loss-of-function mutations in a gene encoding for the lysosomal P-type ATPase named ATP13A2 cause a juvenile and early-onset form of parkinsonism (albeit one that is also characterized by pyramidal degeneration and dementia) (Ramirez et al., 2006).