TNFα rs361525 Promoter Polymorphism and Multiple Sclerosis Risk: A Critical Reading of a 2025 Meta-Analysis
Multiple sclerosis (MS) is a complex immune-mediated and neurodegenerative disorder of the central nervous system characterized by demyelination, axonal injury, and progressive neurological dysfunction. The article by Kumar and colleagues addresses an important dimension of MS biology: the contribution of host genetic variation to disease susceptibility. In particular, the study focuses on the TNFα gene, which encodes tumor necrosis factor alpha, a major pro-inflammatory cytokine implicated in immune regulation, apoptosis, and inflammatory signaling. Because MS pathogenesis involves a complex interaction between immune dysregulation and neuroinflammation, variation in cytokine-related genes remains a plausible mechanistic contributor to disease risk.
Why the rs361525 Variant Matters
The specific genetic variant examined in this study is rs361525, a promoter polymorphism in the TNFα gene, also referred to as the −238 G>A substitution. Promoter variants are of particular scientific interest because they may influence transcriptional activity and alter the amount of cytokine produced rather than changing the structure of the encoded protein. The authors place this polymorphism in the broader context of MS genetics, noting that TNFα resides within the major histocompatibility complex region on chromosome 6, an area already strongly linked to immune-mediated disease. Since elevated TNFα signaling has been associated with MS severity and inflammatory activity, investigating whether rs361525 modifies susceptibility is biologically justified.
Study Design and Methodological Framework
This paper is a systematic review and meta-analysis conducted according to PRISMA principles. The authors searched multiple major databases, including PubMed, Embase, MEDLINE, Web of Science, ScienceDirect, Cochrane resources, PubMed Central, Google Scholar, and SciELO, covering studies published between January 1995 and November 2024. Eligible studies had to be human case-control investigations that specifically evaluated the relationship between TNFα rs361525 and MS risk and provided sufficient genotype data for both case and control groups. Study quality was assessed with the Newcastle–Ottawa Scale, and genotype distributions in controls were checked for Hardy–Weinberg equilibrium. Statistical analysis was conducted using MetaGenyo and RevMan across six genetic models, with heterogeneity assessed by the I² statistic and publication bias evaluated through funnel plots and Egger’s regression.
Composition of the Evidence Base
From an initial pool of 635 records, the authors ultimately included 7 studies in the final meta-analysis. These studies were published between 1997 and 2024 and together represented 878 MS cases and 1,106 controls based on the sample counts listed across the included reports. Most cohorts were of Caucasian origin, with countries represented including Turkey, Iraq, Sweden, Norway, the Netherlands, and Lithuania. Genotyping methods varied and included PCR-RFLP, TaqMan probe assays, SSP-PCR, and other PCR-based approaches. As shown in the PRISMA diagram on page 3 and the study summary tables on pages 4 and 8, the evidence base was limited in size and ethnically narrow, which is highly relevant when interpreting the generalizability of the findings.
Main Findings of the Meta-Analysis
The central result reported by the authors is a positive association between rs361525 and MS risk in the dominant genetic model. They report an odds ratio of 1.03 with a 95% confidence interval of 0.53–1.98 and a p value of 0.04, and on that basis conclude that the polymorphism may contribute to MS susceptibility. By contrast, the allele contrast, heterozygous, homozygous, recessive, and over-dominant models did not show statistically significant associations. The forest plots on pages 4 to 6 illustrate that the dominant model also showed moderate heterogeneity, while several other models had low or absent heterogeneity. The authors further report no clear evidence of publication bias and note that sensitivity analyses suggested that no single study disproportionately drove the pooled estimates.
Biological Interpretation and Network Context
Beyond pooled association testing, the paper extends its analysis by considering the functional context of TNFα. Using STRING-based network analysis, the authors identified interacting or co-expressed genes including LTA, IL1B, TRAF1, TRAF2, TRAF3, TRADD, BIRC3, TNFRSF1A, TNFRSF1B, and KRT18. This network is relevant because it situates TNFα within a broader inflammatory signaling architecture that is plausibly involved in MS pathogenesis. The article therefore argues that even a modest promoter variant could have downstream consequences if it shifts cytokine expression within a tightly regulated immune network. In that sense, the study contributes not merely an association signal, but also a systems-level rationale for why TNFα-related polymorphisms deserve continued attention in neuroimmunology research.
Strengths, Limitations, and Scientific Implications
This meta-analysis is valuable because it consolidates a scattered literature on a specific TNFα promoter variant and applies standard quality filters, sensitivity testing, and bias assessment. At the same time, its limitations are substantial and should temper interpretation. The number of included studies was small, most data came from Caucasian populations, and subgroup analysis by genotyping platform did not reveal significant associations. The authors also acknowledge that they could not stratify by MS subtype and did not integrate environmental, epigenetic, or broader cytokine-related confounders. An additional point for careful readers is that the reported dominant-model confidence interval includes 1.0 despite the stated p value of 0.04, which suggests that the finding should be interpreted cautiously rather than as definitive proof of risk. Overall, the article supports the hypothesis that TNFα rs361525 may be relevant to MS susceptibility, but it also makes clear that larger, ethnically diverse, and mechanistically integrated studies are needed before firm conclusions can be drawn.
Disclaimer: This blog post is based on the provided research article and is intended for informational purposes only. It is not intended to provide medical advice. Please consult with a healthcare professional for any health concerns.
References:
Kumar, H.R.V., Harsha, V.S., Nadig, K. et al. Investigating the association between rs361525 promotor polymorphism with risk of multiple sclerosis: a meta-analysis. Egypt J Med Hum Genet 26, 124 (2025). https://doi.org/10.1186/s43042-025-00752-1
