Niemann-Pick disease, type C (NPC) is a fatal, neurodegenerative disorder characterized by mutations of either NPC1 or NPC2. Decreased function of either protein results in impaired cholesterol transport out of the late endosomal/lysosomal system and therefore accumulation of unesterified cholesterol and glycosphingolipids [as reviewed in [1]–[3]]. Here, NPC1 is linked to Niemann-Pick disease type C.