The interleukin-1 receptor antagonist gene VNTR polymorphism confers a genetic contribution to the risk of immune thrombocytopenia purpura: A systematic review and meta-analysis.

The purpose of this systematic review and meta-analysis was to summarize the existing evidence of the IL1RN variable number (usually two to six) of tandem repeat (VNTR) polymorphism in modulating the susceptibility to immune thrombocytopenia purpura (ITP), with the aim of clarifying its potential as a genetic marker for disease risk stratification. An extensive literature review was performed utilizing the Cochrane Library, NCBI PubMed, and Clarivate Web of Science databases, covering publications up to October 11, 2025. R language was employed to perform pooled estimation and present the results. The odds ratios and corresponding 95% confidence intervals were estimated to assess the strength of the effect. A total of 12 case-control studies comprising 770 ITP cases and 1424 controls were integrated for further synthetic analyses. Summary estimates in all genetic models suggested that the individuals carrying the variant with two repeats are more susceptible to this hematologic disorder. When stratified by geographic region, only the pooled estimates for Latin American and North African countries were statistically significant. No significant publication bias was evident. In conclusion, this meta-analysis indicated that the IL1RN VNTR polymorphism was significantly associated with ITP susceptibility, particularly in Latin American and North African populations.