How are CLOCK and Schlaf related?

The CLOCK gene (Circadian Locomotor Output Cycles Kaput) is a core component of the human circadian clock. It interacts with other clock genes (BMAL1, PER, CRY) to regulate the circadian rhythm, which governs the sleep-wake cycle. Genetic variants in CLOCK have been associated with differences in sleep duration, sleep timing, and risk of sleep disorders such as insomnia or delayed sleep phase syndrome. Evidence is primarily mechanistic from animal models and observational human studies; genome-wide association studies have found modest links. However, the effect sizes are small, and lifestyle factors (light exposure, meal timing) strongly modulate outcomes. Consumer DNA tests claiming to predict sleep traits based on CLOCK variants should be interpreted with caution. The evidence is not strong enough for clinical recommendations. A holistic sleep assessment by a physician remains essential.