Data from a phase 1b study assessing the impact of LRRK2 inhibition in a small cohort of LRRK2-PD patients also revealed a trend toward reduction in the levels of GlcCer and GalCer species in CSF following dosing with DNL201, highlighting the potential of GlcCer and GalCer as CNS biomarkers of LRRK2 inhibition. Here, LRRK2 is linked to Parkinson disease.