ANALYSIS OF CLOCK GENE RS1801260 POLYMORPHISM IN IRANIAN PATIENTS WITH INSOMNIA

Circadian rhythms are natural processes that regulate the sleep-wake cycle and are repeated approximately every 24 hours and controlled by an internal circadian clock. Incorrect functioning of the circadian clock system disrupts the normal sleep pattern. The molecular regulation of this system is done by several clock genes, the most important of which is the CLOCK gene that encodes a transcription factor that plays a central role in regulating the molecular circadian clock. In this study, the rs1801260 polymorphism of the CLOCK gene was investigated in Iranian patients with insomnia.

In this study, 60 blood samples were collected from people with profound problems of insomnia, inability to control sleep and irregular sleep as the patient group and 60 samples from people without any history of insomnia or sleep disorder as the control group. Then DNA was extracted and rs1801260 polymorphism was assessed by ARMS-PCR using specific primers for normal and mutated alleles and the results were analyzed.

According to the results, 50% of patients had GG, 36.7% had AG and 13.3% had AA genotype. In the control group, the frequency of GG, AG and AA genotypes was 30%, 26.7% and 43.3%, respectively. Also, this polymorphism is significantly associated with insomnia in patients (p<0.05) and has no significant relationship with gender, age and lifestyle of patients.

These findings show that the rs1801260 polymorphism and the presence of the G allele in this position have a significant relationship with sleep disorder and it seems to play an important role in occurrence of insomnia in the Iranian population. Therefore, checking the CLOCK gene in patient or susceptible people can be helpful for effective prevention and treatment of the disease.