Genetic regulation of circadian rhythms and the sleep/wake cycle in sleep disorders (a systematic review)
Sleep disorders are a group of pathologies that are difficult to differentiate and diagnose due to the presence of many features. It is noted that sleep disorders have symptomatic similarities with each other and with other diseases, and are also comorbid conditions, which may lead to difficulties in clarifying the diagnosis. Thanks to genome-wide association studies (GWAS) conducted in the previous 20 years, it was found that sleep and its disorders are genetically determined, partially inherited and polygenic. Circadian rhythms are an important mechanism for regulating the sleep/wake cycle, but they are also genetically determined. Circadian rhythms are regulated by clock genes, whose expression follows the circadian rhythm. Due to the above reasons, there is an urgent need to search for biomarkers capable of providing accurate information for the subsequent diagnosis of sleep disorders. This paper provides a review of currently published scientific studies describing genes and genetic variants (SNVs) directly involved in the genetic regulation of circadian rhythms and the sleep/wake cycle, as well as aberrantly expressed genes and SNVs, potentially biomarkers of sleep disorders, which may simplify the process of diagnosing this type of disorders.