The circadian systems genes and their importance of human health.

The circadian rhythm is the timing mechanism that creates approximately 24-hour rhythms in cellular and bodily functions in almost all living species. These internal clock systems enable living organisms to predict and respond to daily changes in their environment, optimizing temporal physiology and behavior. Circadian rhythms are regulated by both genetic and environmental risk factors. Circadian rhythms play an important role in maintaining homeostasis at the systemic and tissue levels. Disruption of this rhythm lays the groundwork for human health and disease. Disruption in these rhythms increases the susceptibility to many diseases, such as cancer, psychiatric disorders, and neurodegenerative diseases. In this chapter, the characteristics of circadian rhythm and its relationship with diseases will be discussed.