NPC1 and nasopharyngeal carcinoma: The NPC Brazil Network (www.ufrgs.br/geneticahcpa/npc/) provides a comprehensive laboratory approach, including screening tests (chitotriosidase, oxysterols), diagnostic tests (Filipin), differential diagnosis (enzyme assays for Gaucher, Niemann-Pick A/B, acid lipase deficiency, and others) and confirmatory genetic analysis of NPC1 and NPC2 genes [10].