title: Single nucleotide polymorphisms in the tumor necrosis factor-alpha gene promoter region alter the risk of psoriasis vulgaris and psoriatic arthritis: a meta-analysis.
abstract: BACKGROUND
  It has been confirmed that tumor necrosis factor-alpha (TNFα), a macrophage-derived pro-inflammatory cytokine, plays an important role in the pathogenesis of psoriasis vulgaris and psoriatic arthritis (PsV&PsA). In contrast, the reported association of TNFα gene promoter region single nucleotide polymorphisms (SNPs) and PsV&PsA has remained controversial. Accordingly, we performed a meta-analysis to provide new evidence that SNPs in the TNFα gene promoter region alter not only the risk of psoriasis vulgaris (PsV) or psoriatic arthritis (PsA) but also of PsV&PsA.
  
  
  METHODS
  Interrelated literature dated to October 2012 was acquired from the PubMed, ScienceDirect, and SpringerLink databases. The number of the genotypes and/or alleles for the TNFα promoter in the PsV and PsA and control subjects was obtained. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to calculate the risk of PsV and/or PsA with TNFα promoter SNPs.
  
  
  RESULTS
  A total of 26 papers of 2159 for PsV (2129 normal controls) and 2360 for PsA (2997 normal controls) were included in our meta-analysis. The results showed that the variant genotype and allele of TNFα -308A/G was protective in pooled groups of patients with PsV&PsA (OR = 0.682, 0.750; 95% CI, 0.596-0.779, 0.653-0.861). However, the variant genotypes and alleles of TNFα -238A/G and -857T/C had an increased risk of PsV&PsA (OR = 2.493, 2.228, 1.536, 1.486, 95% CI, 1.777-3.498, 1.628-3.049, 1.336-1.767, 1.309-1.685). Moreover, the meta-analysis revealed a significant association between TNFα -238A/G and -857T/C polymorphism and PsA susceptibility (OR = 2.242, 2.052, 1.419, 1.465; 95% CI, 1.710-2.941, 1.614-2.610, 1.214-1.658, 1.277-1.681). In contrast, the variant genotypes and alleles of TNFα -308A/G proved to be protective against PsV (OR = 0.574, 0.650, 95% CI, 0.478-0.690, 0.556-0.759), whereas TNFα -238A/G was found to have a risk association (OR = 2.636, 2.223, 95% CI, 1.523-4.561, 1.317-3.751).
  
  
  CONCLUSIONS
  SNPs in the TNFα gene promoter region alter the risk of PsV and/or PsA.
authors.affiliation: Department of Rheumatology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China. lj40038@126.com
authors.forename: Junqing
authors.initials: J
authors.lastname: Zhu
authors.forename: Hongda
authors.initials: H
authors.lastname: Qu
authors.forename: Xiaoguang
authors.initials: X
authors.lastname: Chen
authors.forename: Hao
authors.initials: H
authors.lastname: Wang
authors.forename: Juan
authors.initials: J
authors.lastname: Li
mesh_terms: D015535:Arthritis, Psoriatic / Q000235:genetics*; D005787:Gene Frequency; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease; D006801:Humans; D020641:Polymorphism, Single Nucleotide; D011401:Promoter Regions, Genetic; D011565:Psoriasis / Q000235:genetics; D012306:Risk; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics*
chemical_list: C439524:TNF protein, human; D014409:Tumor Necrosis Factor-alpha