Appropriate wake and sleep cycles are important to physical well-being,
and are modulated by neuronal networks in the brain. A variety of medical
conditions can disrupt sleep or cause excessive daytime sleepiness.
Clinical diagnostic classification schemes have historically lumped genetic
disorders together into a category that considers the sleep dysfunction to
be secondary to a medical condition. The unique nature of sleep
endophenotypes that occur more frequently in particular genetic disorders
has been underappreciated. Increased understanding of the
pathophysiology of wake/sleep dysfunction in rare genetic disorders could
inform studies of the neurological mechanisms that underlie more common
forms of wake and sleep dysfunction. In this review, we highlight genetic
developmental disorders in which sleep endophenotypes have been
described, and then consider genetic neurodegenerative disorders with
sleep characteristics that set them apart from the disruptions to sleep that
are typically associated with aging and dementia.