Notably, a recent study has reported downregulation of Niemann-Pick C1 (NPC1) protein and the subsequent build-up of unesterified cholesterol within lysosomes in an in vitro model of PD, suggesting the concurrence of a Niemann-Pick type C disease (NPCD)-like phenotype and reinforcing the relevance of cholesterol alterations in PD [15]. Here, NPC1 is linked to Parkinson disease.