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Review
. 2018 May 21;14(7):791-798.
doi: 10.7150/ijbs.23744. eCollection 2018.

Health risks associated with genetic alterations in internal clock system by external factors

Suliman Khan  1   2   3 , Ghulam Nabi  1   3 , Lunguang Yao  2 , Rabeea Siddique  4 , Wasim Sajjad  3   5 , Sunjeet Kumar  1 , Pengfei Duan  2 , Hongwei Hou  1
Affiliations
Review

Health risks associated with genetic alterations in internal clock system by external factors

Suliman Khan et al. Int J Biol Sci. .

Abstract

The circadian system maintains the main aspects of physiological and behavioral processes. Both circadian rhythm and sleep impact an organism's health through interaction with environmental factors. Variations in external factors influence the functionality of clock genes and disrupt 24-hour rhythmic cycle. The disrupted circadian rhythm and disregulated sleep affect an organism's health, thereby causing several disorders including cancer, depression and cardiac disorders. Considering the role of clock genes and environmental factors, extensive investigation is required focusing on pathways involved in development of life-threatening disorders. This review identifies the major risks and associated factors related with disruption in circadian system and sleep.

Keywords: Circadian system; clock genes; health risks; sleep.

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Conflict of interest statement

Competing Interests: The authors have declared that no competing interest exists.

Figures

Figure 1
Figure 1
shows the genetic process of circadian system disruption by external factors and the resulted disorders. External influences such as shiftwork and jetlag dysregulate the light-dark cycles which disrupt Bmal1, Clock, Cry and Per genes by causing alterations in RORα, Rev-erbα, kinases, phosphatases and ubiquitin ligases. These disruptions impose their influences on physiological functions. In addition to cancer and obesity external factors mediated disruptions cause abnormal gluconeogenesis, hormonal dysregulation, cardiac, diabetic, sleep and depressive disorders.
Figure 2
Figure 2
represents the disorders associated with disrupted sleep. Dysregulation at any stage of the 5 sleep stages, develop several health risking disorders. Serotonin, acetylcholine, GABA and histamine paly key role in sleep maintenance and their dysregulation can lead to sleep abnormalities or sleep deprivation. Sleep disruption is majorly associated with external influences such as shiftwork, jetlag and overtime work. These factors develop several disorders such as insomnia, sleep apnea, REM and NREM sleep disorders and delayed and advanced phase sleep syndromes. They can also cause sleep deprivation thereby causing obesity.
Figure 3
Figure 3
represents the major disorders that can be caused by external factors. These disorders are developed by the imposed effects of environmental influences on circadian and sleep system.
See this image and copyright information in PMC

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