CLOCK and lysosomal storage disease: To investigate whether the pathological features of lysosomal storage disorders (LSDs) influence the core molecular clock or the circadian behavioural abnormalities reported in some patients, we examined mouse models of Niemann-Pick Type-C (Npc1 mutant, Npc1nih) and Sandhoff (Hexb knockout, Hexb−/−) disease using wheel-running activity measurement, neuropathology and clock gene expression analysis.