Significant Association of Interleukin-4 Gene Intron 3 VNTR Polymorphism with Susceptibility to Knee Osteoarthritis

Abstract

Objective: Interleukin-4 (IL-4) is a strong chondroprotective cytokine and polymorphisms within this gene may be a risk factor for osteoarthritis (OA). We aimed to investigate genotype and allele frequencies of IL- 4 gene intron 3 variable number of tandem repeats (VNTR) polymorphism in patients with knee OA in a Turkish population. Methods: The study included 202 patients with knee OA and 180 healthy controls. Genomic DNA was isolated and IL- 4 gene 70. bp VNTR polymorphism determined by using polymerase chain reaction (PCR) with specific primers followed by restriction fragment length polymorphism (RFLP) analysis. Results: Our result show that there was statistically significant difference between knee OA patients and control group with respect to IL- 4 genotype distribution and allele frequencies (p. = 0.000, OR: 0.20, 95% CI: 0.10-0.41, OR: 0.22, 95% CI: 0.12-0.42, respectively). Conclusions: Our findings suggest that there is an association of IL- 4 gene intron 3 VNTR polymorphism with susceptibility of a person for development of knee OA. As a result, IL- 4 gene intron 3 VNTR polymorphism could be a genetic marker in OA in a Turkish study population. This is the first association study that evaluates the associations between IL-4 gene VNTR polymorphism and knee OA. © 2013.