title: Association of CTLA-4 gene polymorphism with oral submucous fibrosis in Taiwan.
abstract: BACKGROUND
  Oral submucous fibrosis (OSF) is an insidious, pre-cancerous, chronic disease that may affect the entire oral cavity and sometimes extend to the pharynx. It has been reported to be associated with immune function. Cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4; CD (cluster of differentiation) 152) is a negative regulator of T-lymphocyte activation. Particular genotypes of the locus encoding the CTLA-4 glycoprotein have been associated with susceptibility to various autoimmune diseases. This study was designed to investigate the role of CTLA-4 polymorphism in susceptibility to OSF.
  
  
  METHODS
  We genotyped 62 patients with OSF and 147 healthy controls for allelic determinants at the exon 1 +49 polymorphism site by restriction fragment length polymorphism. Genotype and phenotype frequencies were evaluated with Chi-squared test.
  
  
  RESULTS
  The G allele at position +49 of exon 1 was significantly associated with OSF. The frequency of A/A homozygotes was higher in controls than in patients (17.0% vs. 3.2%; chi(2) = 7.65, P = 0.02); the G phenotype was more frequent in patients than in controls (96.8% vs. 83.0%; chi(2) = 9.31, P = 0.002). Compared with controls, the G allele genotype and phenotype frequencies were increased in patients with OSF.
  
  
  CONCLUSIONS
  This is the first report that the CTLA-4 +49 G allele confers an increased risk of OSF in Taiwan.
authors.affiliation: Medical Research, Taipei Mackay Memorial Hospital, Taipei, Taiwan.
authors.forename: Yi-Ning
authors.initials: YN
authors.lastname: Shin
authors.forename: Chung-Ji
authors.initials: CJ
authors.lastname: Liu
authors.forename: Kuo-Wei
authors.initials: KW
authors.lastname: Chang
authors.forename: Yann-Jinn
authors.initials: YJ
authors.lastname: Lee
authors.forename: Hsin-Fu
authors.initials: HF
authors.lastname: Liu
mesh_terms: D000225:Adenine; D000483:Alleles; D015703:Antigens, CD; D000943:Antigens, Differentiation / Q000235:genetics*; D060908:CTLA-4 Antigen; D016009:Chi-Square Distribution; D005091:Exons / Q000235:genetics; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease / Q000235:genetics; D005838:Genotype; D006147:Guanine; D006801:Humans; D007141:Immunoglobulin Fc Fragments / Q000235:genetics*; D008213:Lymphocyte Activation / Q000235:genetics; D008297:Male; D009914:Oral Submucous Fibrosis / Q000235:genetics*; D010641:Phenotype; D011110:Polymorphism, Genetic / Q000235:genetics*; D013601:T-Lymphocytes / Q000276:immunology; D013624:Taiwan
chemical_list: D015703:Antigens, CD; D000943:Antigens, Differentiation; D060908:CTLA-4 Antigen; C556706:CTLA4 protein, human; D007141:Immunoglobulin Fc Fragments; D006147:Guanine; D000225:Adenine