ATP13A2 and Parkinson disease: The importance of ALP impairment in PD is further supported by genetic studies reporting (i) familial genes involved in ALP (i.e., GBA, LRRK2, SNCA, ATP13A2, VPS35, FBXO7,Table 1) [25], (ii) an enrichment of lysosomal genes associated with the risk of PD development in genome wide association studies [26,27], and (iii) mutations in GBA, which encodes for the lysosomal hydrolase glucocerebrosidase (GCase) [28], as the most common genetic risk factor for PD [25,29,30,31].