CTSD and Parkinson disease: Later, immunopositivity for LC3-II indicated that autophagosome formation occurred in the majority of LBs and LNs, and LC3-II colocalized with α-SYN in PD patients (Alvarez-Erviti et al., 2010; Dehay et al., 2010; Tanji et al., 2011), while the amount of lysosomes, and levels and activities of glucocerebrosidase (GCase) or protease cathepsin D (CTSD) were decreased within DA neurons in PD tissues (Dehay et al., 2010; Moors et al., 2019).