Untreated 9-week-old Npc1−/− mice exhibit statistically significant ataxia that presents as a pronounced sigmoidal gait, relative to wild-type mice (P < 0.0001) (Supplementary Fig. 1), whereas 9-week-old Npc1−/− mice treated with ADLL, ALL or ADL from 8 weeks of age (1 week of treatment) displayed significantly reduced ataxia as determined by measuring lateral displacement from a straight trajectory in an automated gait analysis system (Supplementary Fig. 1) (Fig. 1A and B) (P < 0.0001, all treatments). This evidence concerns the gene NPC1 and acute lymphoblastic leukemia.