Association of beta(2)-adrenergic receptor polymorphisms with severe asthma

Background There is considerable interest in the role of different candidat e loci in the development of asthma. This study investigates the associatio n between asthma severity and previously identified polymorphisms at two si tes within the beta(2)-adrenergic receptor (beta(2)AR) gene: the Arg16-->Gl y16 and Gln27-->Glu27 alleles. Methods Restriction enzyme analysis of amplified beta(2)AR gene products (P CR-RFLP) was used to analyse the frequency of the Arg16-->Gly16 and Gln27-- >Glu27 polymorphisms within the beta(2)AR gene in 95 severe asthmatic patie nts (with a markedly increased risk of death from asthma), 59 mild asthmati c patients, and a control group of 92 nonasthmatic subjects. Results The Gly16 polymorphism was significantly associated with asthma sev erity with odds ratios (95% CI) for the Gly16 allele being 1.56 (1.02-2.40, P = 0.04) and 0.98 (0.61-1.57, P = 0.92) for the severe and mild asthma gr oups, respectively. The corresponding odds ratios (95% CI) for Gly16 homozy gotes were 1.91 (0.82-4.41, P = 0.13) and 0.82 (0.35-1.92, P = 0.65) for th e severe and mild asthma groups, respectively. There was no significant ass ociation between either polymorphism at amino acid 27 and asthma or asthma severity. Conclusions We conclude that the polymorphisms of amino acids 16 and 27 of the beta(2)AR gene are not associated with the development of asthma per se , but that the Gly16 polymorphism may play a role in the pathogenesis of as thma severity.