Mutant forms of ATP13A2 that are associated with PD mislocalize to the ER, causing defects in protein degradation and leading to parkinsonism that is levodopa-responsive (Di Fonzo et al., 2009; Matsui et al., 2013; Park et al., 2011; Schröder et al., 2007). The gene discussed is ATP13A2; the disease is Parkinson disease.