title: 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.
authors.affiliation: Gaziosmanpasa University, Faculty of Medicine, Department of Medical Biology, Tokat, Turkey.
authors.forename: Serbulent
authors.initials: S
authors.lastname: Yigit
authors.affiliation: Gaziosmanpasa University, Faculty of Medicine, Department of Physical Therapy and Rehabilitation, Tokat, Turkey.
authors.forename: Ahmet
authors.initials: A
authors.lastname: Inanir
authors.affiliation: Ondokuz Mayis University, Faculty of Medicine, Samsun, Turkey. Electronic address: akintekcan@hotmail.com.
authors.forename: Akın
authors.initials: A
authors.lastname: Tekcan
authors.affiliation: Ondokuz Mayis University, Faculty of Medicine, Department of Physical Therapy and Rehabilitation, Samsun, Turkey.
authors.forename: Ercan
authors.initials: E
authors.lastname: Tural
authors.affiliation: Gaziosmanpasa University, Faculty of Medicine, Department of Physical Therapy and Rehabilitation, Tokat, Turkey.
authors.forename: Gokhan Tuna
authors.initials: GT
authors.lastname: Ozturk
authors.affiliation: Ankara University, Faculty of Veterinary Medicine, Department of Biochemistry, Ankara, Turkey.
authors.forename: Gorkem
authors.initials: G
authors.lastname: Kismali
authors.affiliation: Gaziosmanpasa University, Faculty of Medicine, Department of Medical Biology, Tokat, Turkey.
authors.forename: Nevin
authors.initials: N
authors.lastname: Karakus
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D006801:Humans; D015847:Interleukin-4 / Q000235:genetics*; D007438:Introns; D008297:Male; D008875:Middle Aged; D018598:Minisatellite Repeats / Q000235:genetics*; D020370:Osteoarthritis, Knee / Q000235:genetics*; D011110:Polymorphism, Genetic; D012150:Polymorphism, Restriction Fragment Length; D014421:Turkey
chemical_list: C508598:IL4 protein, human; D015847:Interleukin-4
keywords: ESRD; IL-4; IL-4R; Interleukin-4 (IL-4); Knee osteoarthritis; MS; OA; PCR; Polymorphism; RA; RFLP; SLE; SM; VNTR; end-stage renal disease; interleukin 4; interleukin-4 receptor; multiple sclerosis; osteoarthritis; polymerase chain reaction; restriction fragment length polymorphism; rheumatoid arthritis; severe malaria; systemic lupus erythematosus; variable number tandem repeat