<p>This issue describes in detail the most current thinking on the way genes affect and determine sleep patterns, behaviors, disorders and needs. &nbsp; Sleep researchers continue to study genetic markers that may someday lead to a personalized approach to treatment of sleep disorders. The genetics of restless legs syndrome, narcolepsy, circadian rhythm disorders, obstructive sleep apnea, parasomnias, and insomnia are discussed. A solid understanding of the role genetics and molecular biology play in sleep will aid clinicians in diagnosing and treating these disorders, as well as advising their patients.</p>