In patients with NPC1, CNS treatment is crucial, as the main cause of death is related to neurological dysfunction.13 However, multiple organ dysfunction, mainly liver dysfunction and pulmonary damage, is another possible cause of death, especially for perinatal patients who show severe liver dysfunction with cholestasis40 and lung damage.41 Our AAV-treated Npc1−/− mice showed body weight loss starting a few weeks before their death, which may indicate the dysfunction of those organs. The gene discussed is NPC1; the disease is Decreased liver function.