title: Association between fibromyalgia syndrome and polymorphism of the IL-4 gene in a Turkish population.
abstract: OBJECTIVE
  Fibromyalgia (FM) syndrome is a form of non-articular rheumatism characterized by long term and widespread musculoskeletal pain, morning stiffness, sleep disturbance, paresthesia, and pressure hyperalgesia at characteristic sites, called soft tissue tender points. The etiology of FM is still obscure. Genetic factors may predispose individuals to FM. Cytokines may play a role in the pathophysiology of FM. The aim of this study was to investigate the interleukin-4 (IL-4) 70 bp VNTR variations in Turkish patients with FM and evaluate if there was an association with clinical features, especially between these polymorphisms.
  
  
  METHODS
  The study included 300 patients with FM and 270 healthy controls. Genomic DNA was isolated and genotyped using polymerase chain reaction (PCR) for the IL-4 gene 70 bp VNTR polymorphisms.
  
  
  RESULTS
  There was statistically significant difference between the groups with respect to IL-4 genotype distribution and allele frequencies (p<0.0001). The homozygous P1P1 genotype and P1 allele were significantly higher in FM patients than in healthy controls (p=0.04; OR: 3.25, 95% CI: 1-10, p<0.0001; OR:4.84, 95% CI:3-7.7). There was not any difference between the groups respect to IL-4 genotype distribution and allele frequencies (p>0.05) and clinical characteristics.
  
  
  CONCLUSIONS
  Our findings suggest that there is an association of IL-4 gene 70 bp VNTR polymorphism with susceptibility of a person for development of FM. As a result, further studies are necessary to determine whether IL-4 may be a genetic marker for FM in the Turkish population.
authors: Gaziosmanpasa University, Faculty of Medicine, Department of Medical Biology, Tokat, Turkey. yigit.serbulent@gmail.com
authors: Serbulent
authors: S
authors: Yigit
authors: Ahmet
authors: A
authors: Inanir
authors: Akın
authors: A
authors: Tekcan
authors: Sema
authors: S
authors: Inanir
authors: Sengul
authors: S
authors: Tural
authors: Omer
authors: O
authors: Ates
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D005260:Female; D005356:Fibromyalgia / Q000235:genetics*; D005787:Gene Frequency; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease; D006801:Humans; D015847:Interleukin-4 / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D018598:Minisatellite Repeats; D011110:Polymorphism, Genetic; D017422:Sequence Analysis, DNA; D014421:Turkey
chemical_list: C508598:IL4 protein, human; D015847:Interleukin-4
keywords: ACR; American College of Rheumatology; CNS; Central nervous system; EDTA; Ethylendiamine-tetraacetate; FM; FMF; Familial Mediterranean fever; Fibromyalgia; Fibromyalgia syndrome; IL-1a; IL-1b; IL-2; IL-4; IL-6; IL-8; Interleukin 1a; Interleukin 1b; Interleukin 2; Interleukin 6; Interleukin 8; Interleukin-4; Interleukin-4 gene (IL-4); MEFV; Mediterranean fever; PCR; Polymerase chain reaction; Polymorphism; RFLP; Restriction fragment length polymorphism; SD; Standard deviation; TNF-a; Tumor necrosis factor a