Tumor necrosis factor alpha gene promoter polymorphis in patients with achizophrenia in a Kenyan population

Abstract

Aim: Tumour necrosis factor alpha (TNF-α) promoter single nucleotide polymorphisms (SNPs) have been reported to play pathological roles in schizophrenia with contradicting findings in several studies. The status of TNF-α SNPs remains unknown in our population. Therefore, this study sought to determine the association of TNF-α gene promoter single nucleotide polymorphisms -308A/G (rs 1800629) and -1031C/T (rs 1799964) in patients with schizophrenia at MTRH, Kenya. Methods: A case-control study at MTRH included 82 schizophrenia patients and 82 age and sexmatched healthy controls. Participants' demographic data were collected using an intervieweradministered questionnaire, and DNA was extracted from saliva samples for TNF-α SNP genotyping using the Allelic Discrimination Assay®. Results: There were no statistically significant differences in genotype distribution and allele frequencies between cases and controls for -308A/G and -1031C/T polymorphisms (p = 0.261) and (p = 0.678) respectively. The genotype associations with schizophrenia were: at - 308(rs1800629), A/G had OR 1.67, 95% CI (0.88-3.16) p=0.114. At -1031(rs1799964), genotype C/C and C/T, had OR 0.66, 95% CI (0.22-1.97) p=0.455 and OR 0.75, 95% CI (0.48-1.18) p=0.255 while a combination of C/T- C/C, had OR 0.743, 95% CI (0.40-1.38) p=0.346. Conclusion: These results demonstrate that SNPs in the TNF-α promoter region at the studied loci are unrelated to schizophrenia. These SNPs may not serve as useful biomarkers for diagnosis or targeted therapy. Further analysis of these SNPs focusing on specific schizophrenia symptoms, rather than the entire syndrome, may be needed.