title: Association between beta2-adrenoceptor polymorphisms and asthma diagnosis among Mexican adults.
abstract: BACKGROUND
  Recent studies demonstrate that genetic variations in the human beta(2)-adrenergic receptor (beta(2)AR) structure at codons 16 and 27 alter receptor function in vitro and are associated with asthma severity and airway hyperresponsiveness but have not been linked to asthma diagnosis. The nature of the relation in a more homogeneous population is uncertain.
  
  
  OBJECTIVE
  We determined frequencies of these polymorphisms to explore the association between beta(2)AR haplotypes and asthma diagnosis and phenotype.
  
  
  METHODS
  This is a population-based, case-control study that involves a total sample of 907 unrelated Mexican Mestizos. Genotyping at beta(2)AR was identified by polymerase chain reaction-restriction fragment length polymorphism analysis. Multivariate logistic regression analysis was used to estimate the odds ratio (OR) of the association between beta(2)AR haplotype status and asthma diagnosis.
  
  
  RESULTS
  A significant inverse association was found between subjects with Glu27 allele (OR, 0.5; 95% CI, 0.4 to 0.7) and Gly16-Glu27 alleles (OR, 0.5; 95% CI, 0.3 to 0.8) and asthma. Sex differences in this association were explored, given the complex relation between sex and asthma. Among men, a positive association was present between the "Gly16 allele without Glu27" (OR, 2.9; 95% CI, 1.26 to 6.8) and asthma. In contrast, a lower risk of asthma was found among women Gly16-Glu27 alleles (OR, 0.3; 95% CI, 0.2 to 0.6). Nocturnal asthma was associated with the Gly16 allele (OR, 1.8; 95% CI, 1.3 to 2.6).
  
  
  CONCLUSIONS
  Variation in the beta(2)AR gene is associated in the pathogenesis of asthma and acts as a disease modifier in nocturnal asthma.
authors.affiliation: Departamento de Bioquímica, Facultad de Medicina, Universidad Autónoma de Nuevo León (UANL), Monterrey, México.
authors.forename: Alfredo A
authors.initials: AA
authors.lastname: Santillan
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Camargo
authors.forename: Alicia
authors.initials: A
authors.lastname: Ramirez-Rivera
authors.forename: Ivan
authors.initials: I
authors.lastname: Delgado-Enciso
authors.forename: Augusto
authors.initials: A
authors.lastname: Rojas-Martinez
authors.forename: Felipe
authors.initials: F
authors.lastname: Cantu-Diaz
authors.forename: Hugo A
authors.initials: HA
authors.lastname: Barrera-Saldaña
mesh_terms: D000328:Adult; D001249:Asthma / Q000175:diagnosis* / Q000208:ethnology / Q000235:genetics*; D016022:Case-Control Studies; D003062:Codon / Q000235:genetics; D005260:Female; D005787:Gene Frequency; D008040:Genetic Linkage; D005828:Genetics, Population; D006239:Haplotypes; D006801:Humans; D008297:Male; D008800:Mexico / Q000453:epidemiology; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic / Q000235:genetics*; D012150:Polymorphism, Restriction Fragment Length; D018343:Receptors, Adrenergic, beta-2 / Q000235:genetics*
chemical_list: D003062:Codon; D018343:Receptors, Adrenergic, beta-2