NPC2 and nasopharyngeal carcinoma: Causal variants for Niemann-Pick type C (NPC) have been identified within the NPC intracellular cholesterol transporter 1 (NPC1) gene and the NPC intracellular cholesterol transporter 2 (NPC2) gene, whereas the causal variant for the Novia-Scotian Niemann-Pick type D disease has been identified only in the NPC1 gene [6, 11].