NPC1 and Niemann-Pick disease, type C1: NPC1(Niemann–Pick disease type C1) is a neurodegenerative inherited recessive disorder caused by mutations in the NPC1 or NPC2 genes, characterized by disturbed intracellular transport of cholesterol and other lipids, resulting in the accumulation of unesterified cholesterol in the central nervous system (Vanier, 2015).