Sleep is essential for life. A good night's sleep is pleasurable and sleep deprivation is stressful. Prolonged sleep loss impairs temperature control, metabolism, immunity, and ultimately leads to death. Extensive observational and epidemiological evidence indicates that optimal sleep duration of 8 hours is associated with the maintenance of good health. In our society, however, most people only get 6.5 - 7 hours. Suboptimal sleep duration has a strong association with mortality and morbidity. Lack of sleep has been linked to cardiovascular diseases, obesity, hypertension, type 2 diabetes, and other health/cognition conditions. It is clear that the biological need for sleep varies dramatically among humans. Sleep and circadian disorders can include Familial Advanced Sleep Phase (FASP), Delayed Sleep Phase (DSP), Advanced Sleep Phase (ASP), Natural Short Sleepers (NSS) or Long Sleeping. In example, Natural Short Sleepers (NSS) have a lifelong tendency to sleep only 4 - 6 hours per night and to awaken refreshed and energetic. Natural Long Sleepers biologically require 9 - 10 hours/night to feel well rested. The 'Sleep and Circadian Disorders Study' (SACDS) at the University of California San Francisco, set out to investigate the mechanisms involved in regulating sleep duration, patterns and sleep quality regulation by identifying and characterization of individuals and families with unusual sleep and circadian rhythm behavior patterns. SACDS participants were screened with a "General Sleep Questionnaire" that inquired about multiple aspects of sleep, including habitual work-day versus non-work day sleep-wake schedules, permits calculation of subjective habitual initial sleep onset, final sleep offset, and number of awakenings. There was an additional screening process including demographic data, sleep, mood, behavioral and general medical questionnaires, plus the study consent. After the extensive screening of 117 participants, blood samples were collected from 38 individuals and of those 10 samples were chosen for whole exome sequencing analysis.

Sleep and Circadian Disorders Study (SACDS)

An hPer2 Phosphorylation Site Mutation in Familial Advanced Sleep Phase Syndrome

Familial advanced sleep-phase syndrome: A short-period circadian rhythm variant in humans

The Transcriptional Repressor DEC2 Regulates Sleep Length in Mammals

A PERIOD3 variant causes a circadian phenotype and is associated with a seasonal mood trait

Genetics of human sleep behavioral phenotypes.