NPC1 and Niemann-Pick disease type C: Our present study focusses on abnormalities in GCase in the liver of mice that lack the lysosomal transmembrane protein NPC1 and consequently develop Niemann–Pick disease type C. Earlier investigations already showed that the livers of Npc1−/− mice contain increased levels of GlcCer, the substrate of GCase, along with accumulation of cholesterol [7,24].