Brazilian Journal of Pathology and Laboratory Medicine

Association of TNF-α (G308A) Gene Polymorphism with Susceptibility to Open-Angle Glaucoma in Iraqi Patients: A Laboratory-Based Genetic Study

Hawraa. A. Ali
Department of Microbiology, College of Medicine, University of Al-Qadisiyah, Iraq

Dr. Ibrahim A. Altamemi
Department of Microbiology, College of Medicine, University of Al-Qadisiyah, Iraq

ABSTRACT

Background: Open-angle glaucoma (OAG) is a progressive optic neuropathy that leads to irreversible vision loss. Genetic predisposition and pro-inflammatory cytokines, particularly tumor necrosis factor-alpha (TNF-α), have been implicated in glaucomatous neurodegeneration. The G308A single nucleotide polymorphism (SNP) of the TNF-α gene may play a role in the pathogenesis of OAG by influencing inflammatory and apoptotic pathways. Objective: This study aimed to evaluate the association between TNF-α (G308A) gene polymorphism and susceptibility to OAG in Iraqi patients and its correlation with serum TNF-α levels and clinical parameters of glaucoma progression. Methods: A case-control study was conducted on 100 OAG patients and 100 age- and sex-matched healthy controls. Genotyping of TNF-α (G308A) polymorphism was performed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. Serum TNF-α levels were measured using enzyme-linked immunosorbent assay (ELISA). Clinical parameters, including intraocular pressure (IOP), cup-to-disc ratio, and retinal nerve fiber layer (RNFL) thickness, were assessed using tonometry and optical coherence tomography (OCT). Results: The A allele frequency was significantly higher in OAG patients compared to controls (p < 0.001, OR = 2.15), indicating a possible genetic predisposition. Serum TNF-α levels were significantly elevated in OAG patients compared to controls (p < 0.01), with the highest levels observed in individuals carrying the AA genotype. A significant correlation was observed between TNF-α levels and clinical glaucoma severity, with higher TNF-α concentrations associated with increased IOP and optic nerve damage. Conclusion: The TNF-α (G308A) polymorphism may serve as a genetic risk factor for OAG in the Iraqi population. The AA genotype is associated with elevated TNF-α levels, suggesting its role in inflammatory-mediated optic nerve damage. These findings highlight the potential role of TNF-α as a biomarker for early glaucoma detection and progression monitoring. Further genetic and functional studies are needed to establish TNF-α as a therapeutic target in glaucoma management.

Keywords: Chronic Optic Neuropathy, Primary Open Angle Glaucoma (POAG), Genetic and Environmental Variables.

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