CLOCK (Circadian Locomotor Output Cycles Kaput): CLOCK is a gene that plays a central role in regulating circadian rhythms — the physical, mental, and behavioural changes that follow a 24-hour cycle. It helps control sleep-wake patterns and various physiological processes, including metabolism. Mutations in the CLOCK gene can disrupt normal circadian rhythms, contributing to sleep disorders, metabolic syndrome, and mood disturbances.