title: Influence of IL-1RN intron 2 variable number of tandem repeats (VNTR) polymorphism on bipolar disorder.
abstract: OBJECTIVE
  Several lines of evidence point to the role of neurobiological mechanisms and genetic background in bipolar disorder (BD). The interleukin-1 receptor antagonist (IL-1Ra) is the principal regulator of IL-1α and IL-1β bioactivities. This study aimed to investigate the potential role of the variable number of tandem repeats (VNTR) polymorphisms of the IL-1Ra gene (IL1RN) in conferring susceptibility to BD.
  
  
  METHODS
  In total, 217 patients meeting DSM-IV-TR criteria for BD and 212 controls were recruited for the study. Genotyping of IL1RN was determined by polymerase chain reaction amplification of VNTR of 86 base pairs in intron 2 of IL1RN.
  
  
  RESULTS
  The genotype distribution of IL1RN polymorphism was significantly different between BD patients and controls. The IL1RN*1/2 genotype was more prevalent in BD patients than in controls (44.2 vs. 30.2%, p = 0.003). Multiple logistic regression analysis demonstrated that IL1RN*1/2 heterozygotes had a significantly higher risk for BD (OR 1.83 and 95% CI 1.22-2.74, p = 0.003). Further stratification of the BD patients into IL1RN*2 allele carrier and noncarrier subgroups revealed a strong association between IL1RN*2 carriage and prolongation of the disease (p = 0.02).
  
  
  CONCLUSIONS
  These findings suggest a positive association between VNTR polymorphism in IL1RN and BD. Additional studies, particularly with a prospective approach, are necessary to clarify the precise role of the VNTR polymorphism on the disease in different ethnic populations.
authors: Molecular and Cell Biology Research Center, Mazandaran University of Medical Sciences, Sari, Iran.
authors: A
authors: A
authors: Rafiei
authors: S H
authors: SH
authors: Hosseini
authors: M
authors: M
authors: Taheri
authors: Z
authors: Z
authors: Hosseni-khah
authors: M
authors: M
authors: Hajilooi
authors: Z
authors: Z
authors: Mazaheri
mesh_terms: D000328:Adult; D001714:Bipolar Disorder / Q000235:genetics*; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D053590:Interleukin 1 Receptor Antagonist Protein / Q000235:genetics*; D007438:Introns / Q000235:genetics*; D007492:Iran; D008297:Male; D008875:Middle Aged; D018598:Minisatellite Repeats / Q000235:genetics*; D011569:Psychiatric Status Rating Scales; D055815:Young Adult
chemical_list: D053590:Interleukin 1 Receptor Antagonist Protein