Association between serotonin receptor gene (HTR2A) polymorphisms (RS6313 and RS6311) with psychosis risk: A Case-Control study in Iraq

The serotoninergic system plays a crucial role in the pathogenesis of mental disorders.Accordingly, this study aimed to investigate the association between psychosis and the (rs6313, rs6311) polymorphisms of the 5HT2A gene.This study included 60 patients (35 males and 25 females) and 50 apparently healthy controls (22 males and 28 females).Blood samples were collected and then genomic DNA from White Blood Cells (WBCs) was extracted.The 5HT2A gene polymorphisms were characterized using PCR-RFLP technique.Statistical analysis showed a significant association between rs6313 polymorphism and patient with psychosis.In co-dominant odds ratio (OR) = 14.400, p=0.013 and dominant models (OR =0.082, p = 0.006), allele frequency analysis revealed the G allele was associated with increased risk of psychosis, whereas the A allele as a protective effect.Also, a significant association was observed (p = 0.05) aged 31-50 years among patients compared with controls.Regarding of rs6311 polymorphism , significant association were observed between patient and control groups under both recessive (p = 0.0001) and the co-dominant particularly for the T/T genotype (OR =6.399, p = 0.0001) and the C/T genotype (OR=10.750p = 0.030).Regarding allele frequency analysis was showed a significate (p = 0.0001) between patients and controls that refers the C allele as a risk and the T allele as a protective effect .A significant difference association were observed)across sex (p = 0.036) and aged groups 10-30-and 31-50-year (p= 0.045 and p = 0.009, respectively)between patients and controls.The study indicates that the HTR2A rs6313 and rs6311 polymorphisms are significantly associated with risk of psychosis in Iraqi patients, particularly the C/T genotype and C allele of rs6311, as well as G allele frequency of rs6313, were found to be significantly associated with an increased susceptibility to psychosis.Moreover, the genetic variation (age and sex dependent) may contribute to the pathogenesis of psychosis.