CTSE and Parkinson disease: Recently, increased β-galactosidase (EC = 3.2.1.23) and cathepsin E (EC = 3.4.23.34) activities and a reduced α-fucosidase (EC = 3.2.1.51) activity have been found in the CSF of PD patients compared to healthy controls, and β-glucocerebrosidase showed a trend toward reduction in the PD group (17).