Screening of Clock Gene Polymorphisms Demonstrates Association of a PER3 Polymorphism with Morningness–Eveningness Preference and Circadian Rhythm Sleep Disorder

A system of self-sustained biological clocks controls the 24-h rhythms of behavioral and physiological processes such as the sleep-wake cycle. The circadian clock system is regulated by transcriptional and translational negative feedback loops of multiple clock genes. Polymorphisms in circadian clock genes have been associated with morningness-eveningness (diurnal) preference, familial advanced sleep phase type (ASPT), and delayed sleep phase...