Association between 5-hydroxytryptamine gene polymorphism rs140700 and primary insomnia in Chinese population

Background: Primary insomnia is a worldwide problem and it has a considerable negative impact on one's physical and mental health. Studies have shown that non-synonymous Single-nucleotide polymorphisms in 5-hydroxytryptamine (serotonin or 5-HT) are related to primary insomnia. Previous studies have shown that 5-HT polymorphism (rs140700) is related to depression, and insomnia is often accompanied by depression and anxiety. The relationship between this site and primary insomnia is unknown. We speculated that this site may be related to primary insomnia, so we investigated the relationship between rs140700 and primary insomnia. 

Aims: To explore the relationship between the 5-HT gene polymorphism rs140700 and primary insomnia. 

Methods: In this study, we included 57 patients with primary insomnia and 54 age- and gender-matched normal controls. The subjects who belonged to the Chinese population were subjected to polysomnography for three consecutive nights. Their sleep quality was assessed, and the genotypes of the 5-hydroxytryptamine (5-HT) gene polymorphism rs140700 were determined by the flight mass spectrometry. 

Results: The genotype distributions of the 5-HT gene polymorphism rs140700 were in Hardy–Weinberg equilibrium in both patients and controls (P > 0.05). The allele and genotype distributions of this variant were comparable between the patients and controls in all subjects and between genders (all P > 0.05). The influence of rs140700 on percentage of stage 1 (P = 0.015) change and arousal index (P = 0.028) of primary insomnia was statistically significant. The logistic multi-factor regression analysis results revealed that 5-HT gene polymorphism rs140700 was not a risk factor for primary insomnia in the Chinese population (P = 0.589). 

Conclusions: The 5-HT gene polymorphism rs140700 may not be a susceptibility locus for primary insomnia in the Chinese population.