ATP6AP2 and Parkinson disease: Several additional genes linked to genetic PD or atypical forms of PD are involved in ALP functions, cellular trafficking, endo- and exocytosis, including ATP13A2, PLA2G6, ATP6AP2 and two novel PD genes, VPS13C and ATP10B (reviewed recently by Smolders and Van Broeckhoven, 2020 [44]).