NPC1 and nasopharyngeal carcinoma: The incidence of classical NPC has been estimated to be on the order of 1/100,000, while there may be a more frequent late-onset variant.1, 2 NPC can be caused by mutation in either NPC1 or NPC2, with the majority of cases (~95%) being due to mutation of NPC1. 1 Impaired function of either NPC1 or NPC2 results in the endolysomal storage of unesterified cholesterol and other lipids.1, 3, 4 The NPC1 phenotype is heterogeneous with respect to both age of onset (infantile, childhood, adolescent, adult) and disease manifestations.