title: Polymorphisms in manganese superoxide dismutase and catalase genes: functional study in Hong Kong Chinese asthma patients.
abstract: BACKGROUND
  Reactive oxygen species may contribute to the pathogenesis of asthma. Functional genetic polymorphisms of antioxidant enzymes, superoxide dismutase (SOD) and catalase are good candidates for asthma susceptibility.
  
  
  OBJECTIVE
  To investigate the association of the manganese-containing form of SOD (MnSOD) gene at amino acid position 16 (Val16Ala) and catalase gene in the promoter at A-21T and C-262T polymorphisms and asthma in a Hong Kong Chinese population.
  
  
  METHODS
  The association study was conducted in a case-control design in asthma patients (n=251) and healthy controls (n=316) by genotyping. The functional significance was assessed by determining erythrocyte SOD and catalase activity.
  
  
  RESULTS
  The Val allele of MnSOD at Val16Ala and the A allele of catalase gene at A-21T were not different between patients and controls, while the C allele of catalase gene at C-262T was found to be significantly different between patients and controls (P=0.033). The less frequent variant of catalase gene (-262T) was found to be protective from the development of asthma in a Hong Kong Chinese non-smoking population (adjusted odds ratio=0.35, 0.15-0.85; P=0.017). Asthma patients had elevated erythrocyte SOD and catalase activities in comparison with healthy controls (P<0.01). However, their activities were not associated with different genotypes within healthy controls or asthma patients.
  
  
  CONCLUSIONS
  This is the first report showing that SOD and catalase functional activities are not associated with their respective genetic polymorphisms but related to the presence of asthma in a Hong Kong Chinese population.
authors.affiliation: Division of Respiratory and Critical Care Medicine, Department of Medicine, The University of Hong Kong, Hong Kong, SAR, China.
authors.forename: J C W
authors.initials: JC
authors.lastname: Mak
authors.forename: H C M
authors.initials: HC
authors.lastname: Leung
authors.forename: S P
authors.initials: SP
authors.lastname: Ho
authors.forename: F W S
authors.initials: FW
authors.lastname: Ko
authors.forename: A H K
authors.initials: AH
authors.lastname: Cheung
authors.forename: M S M
authors.initials: MS
authors.lastname: Ip
authors.forename: M M W
authors.initials: MM
authors.lastname: Chan-Yeung
mesh_terms: D000483:Alleles; D001249:Asthma / Q000201:enzymology / Q000453:epidemiology / Q000235:genetics*; D016022:Case-Control Studies; D002374:Catalase / Q000235:genetics*; D005260:Female; D016166:Free Radical Scavengers; D020022:Genetic Predisposition to Disease / Q000235:genetics; D005838:Genotype; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic / Q000235:genetics*; D012307:Risk Factors; D012907:Smoking / Q000453:epidemiology / Q000235:genetics; D013482:Superoxide Dismutase / Q000235:genetics*
chemical_list: D016166:Free Radical Scavengers; D002374:Catalase; D013482:Superoxide Dismutase