title: TNF-alpha gene polymorphism (-308G/A) and toxoplasmic retinochoroiditis.
abstract: OBJECTIVE
  To investigate the possible association between TNF-alpha (-308G/A) polymorphism and toxoplasmic retinochoroiditis (TR) in humans.
  
  
  METHODS
  A cross-sectional study was performed which included 100 Brazilian patients with diagnosis of TR and 100 matched control subjects with positive serology to toxoplasmosis and no sign of uveitis. Genomic DNA was obtained from oral swabs of all subjects and amplified using the polymerase chain reaction (PCR) with specific primers flanking the locus -308 of TNF-alpha. PCR products were submitted to restriction endonuclease digestion and analysed by polyacrylamide gel electrophoresis to distinguish alleles, allowing the determination of the genotypes.
  
  
  RESULTS
  There was no significant difference in the genotype (chi(2) = 0.79, p = 0.67), allele (chi(2) = 0.095, p = 0.75) and allele carriage (chi(2) = 0.70, p = 0.40) frequencies in TR patients compared with control subjects. Frequencies of the genotype (chi(2) = 2.05, p = 0.35) and allele (chi(2) = 0.13, p = 0.71) did not differ significantly between TR patients with and without recurrent episodes.
  
  
  CONCLUSIONS
  This is the first study to investigate the association between TNF-alpha polymorphism and the occurrence of TR in humans. TNF-alpha gene polymorphism (-308G/A) does not seem to be associated with the occurrence or recurrence of TR.
authors.affiliation: Uveitis Section, Department of Ophthalmology, School of Medicine, Belo Horizonte, Brazil. cordeiro.cy@gmail.com
authors.forename: C A
authors.initials: CA
authors.lastname: Cordeiro
authors.forename: P R
authors.initials: PR
authors.lastname: Moreira
authors.forename: G C
authors.initials: GC
authors.lastname: Costa
authors.forename: W O
authors.initials: WO
authors.lastname: Dutra
authors.forename: W R
authors.initials: WR
authors.lastname: Campos
authors.forename: F
authors.initials: F
authors.lastname: Oréfice
authors.forename: A L
authors.initials: AL
authors.lastname: Teixeira
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D002825:Chorioretinitis / Q000235:genetics* / Q000469:parasitology / Q000503:physiopathology; D003430:Cross-Sectional Studies; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction / Q000379:methods; D011110:Polymorphism, Genetic; D014126:Toxoplasmosis, Ocular / Q000235:genetics* / Q000503:physiopathology; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics*; D014792:Visual Acuity
chemical_list: D014409:Tumor Necrosis Factor-alpha