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 sex-matched healthy controls. Participants’ demographic data were collected using an interviewer-administered 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.

Competing Interest Statement

The authors have declared no competing interest.

Funding Statement

This study was supported by the Neurogenetics of African population - Psychosis (NeuroGAP-P) project and the funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript.

Author Declarations

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

Institutional Research and Ethics Committee of Moi University/ Moi Teaching and Referral Hospital gave approval for this work(approval number MU/MTRH-FAN: 0003881).

I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.

Yes

I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

Yes

I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.

Yes

Data Availability

All data produced in the present study are available upon reasonable request to the authors.

AbbreviationsDSM-VDiagnostic Statistical Manual -Version 5HLAHuman Leukocyte AntigenILInterleukinMAPKMitogen-activated protein kinasePCRPolymerase Chain ReactionNFQNon-Fluorescent QuencherTNFRTumor Necrosis Factor Receptor