title: Associations between NRAMP1 Polymorphisms and Susceptibility to Ulcerative Colitis/Crohn's Disease: A Meta-Analysis.
abstract: OBJECTIVE
  Multiple environmental and genetic factors contribute to the risks of ulcerative colitis (UC) and Crohn's disease (CD). Several allelic variants have been identified in natural resistance associated macrophage protein 1 (NRAMP1) gene; however, their association with UC/CD remains conflicting. The purpose of this study was to evaluate whether NRAMP1 polymorphisms are associated with the susceptibility to UC/CD.
  
  
  METHODS
  A meta-analysis on the association between the NRAMP1 polymorphisms and susceptibility to UC/CD was performed. Relevant studies were retrieved from the databases. After eligible data were extracted, Mantel-Haenszel statistics and random/fixed effects model were applied to calculate the pooled odds radio (OR) and 95% confidence interval (95% CI).
  
  
  RESULTS
  Seven articles containing 536 UC cases, 997 CD cases, and 1361 controls were collected. No significant association between allele 2 frequency of NRAMP1 and susceptibility to UC/CD was detected in overall population (all p > 0.05). However, increased UC/CD risk for allele 3 was observed in Caucasian population (OR = 1.27, 95% CI = 1.08~1.50, p = 0.04), whereas decreased UC/CD risk was detected in non-Caucasian population (OR = 0.72, 95% CI = 0.60~0.87, p < 0.001), under "allele 3 vs. other alleles" model. Moreover, a significant increase in CD risk for T carrier frequency of -237 C/T (OR = 0.44, 95% CI, 0.26~0.75, p = 0.003) was detected, but not 274 C/T and 1729+55del4 (TGTG) +/del.
  
  
  CONCLUSIONS
  The polymorphism of -237 C/T is related to the risk of CD; and the association of allele 3 with UC/CD risk differs in Caucasian and non-Caucasian population, which might be the potential biomarkers for clinical diagnosis of UC/CD.
authors.affiliation: a Department of Gastroenterology , Tianjin Union Medicine Center & Tianjin People's Hospital , Tianjin , China.
authors.forename: Manyi
authors.initials: M
authors.lastname: Sun
authors.affiliation: b Department of Pathology , Tianjin Union Medicine Center & Tianjin People's Hospital , Tianjin , China.
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.affiliation: b Department of Pathology , Tianjin Union Medicine Center & Tianjin People's Hospital , Tianjin , China.
authors.forename: Songli
authors.initials: S
authors.lastname: Shi
mesh_terms: D000483:Alleles; D027682:Cation Transport Proteins / Q000235:genetics*; D003093:Colitis, Ulcerative / Q000235:genetics*; D003424:Crohn Disease / Q000235:genetics*; D005787:Gene Frequency; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D016017:Odds Ratio; D020641:Polymorphism, Single Nucleotide; D017594:Publication Bias; D012306:Risk; D000099173:Natural Resistance-associated Macrophage Protein 1
chemical_list: D027682:Cation Transport Proteins; D000099173:Natural Resistance-associated Macrophage Protein 1
keywords: Crohn’s disease; NRAMP1; meta-analysis; polymorphisms; ulcerative colitis