Niemann–Pick type C (NPC) is an autosomal recessive lysosomal storage disease. Fibroblasts from individuals with Niemann–Pick type C exhibit defective intracellular cholesterol transport. Linkage analysis has led to the recent cloning of the NPC1 gene on human chromosome 18, which is the major disease locus. Analysis of NPC1 reveals homologies with key regulators of cholesterol homeostasis and aDrosophila morphogenreceptor. Curr Opin Lipidol 9:131–135. © 1998 Rapid Science Ltd