However, in vitro experiments using non-neuronal, Npc1-deficient Chinese hamster ovary cells or fibroblasts derived from patients with NPC demonstrated N-acetyl-l-leucine and N-acetyl-dl-leucine also reverse disease-related cellular phenotypes in non-neuronal cells, including expanded lysosomal volume, with superior efficacy resulting from the L-enantiomer [19]. The gene discussed is NPC1; the disease is nasopharyngeal carcinoma.