Lack of Association Between FNDC5 Gene Polymorphisms, Serum Irisin Levels and Allergic Rhinitis

Aim: Allergic rhinitis (AR) is an inflammatory nasal mucosa disease caused by type 1 immunoglobulin E-mediated reactions to allergen exposure. Irisin is a hormone released by skeletal muscles in response to exercise. There are studies that demonstrate the relationship of irisin with inflammation. We aimed to investigate the potential association between irisin coding fibronectin type III domain 5 (FNDC5) gene polymorphisms, serum irisin levels, and AR. Method: A case-control study was designed, involving 100 AR patients and 100 healthy controls. Genotyping of rs726344 and rs1746661 SNPs within the FNDC5 gene was performed using PCR-RFLP method. Serum irisin levels were measured using ELISA. Results: Genotyping of rs726344 SNP in patients revealed 90% GG and 10% GA genotypes, while in controls, it was 94% GG and 6% GA. The AA genotype was not detected in any case. For rs1746661 SNP, patients had 57% GG, 39% GT, and 4% TT genotypes, while controls had 58% GG, 36% GT, and 6% TT genotypes. No significant difference was found in rs726344 and rs1746661 SNPs between the patients and the control group. Serum irisin level was 406.3±56.09 ng/ml in patients and 354.3±46.06 ng/ml in controls with no significant difference. Conclusion: This is the first study aiming to investigate the relationship between the irisin protein, its encoding gene, and AR. No significant association was identified between FNDC5 gene polymorphisms, serum irisin levels, and allergic rhinitis. While these findings suggest a limited role of these factors in AR, further studies are needed for more comprehensive understanding of the irisin-AR relationship.