Polymorphisms of the beta(2)-Adrenergic Receptor Correlated to Nocturnal Asthma and the Response of Terbutaline Nebulizer

Abstract

Background: Inhaled beta(2)-adrenergic receptor (beta(2)-AR) agonists are the mainstay of treatment of acute asthma. Polymorphisms of the beta(2)-AR, especially codons 16, 27, and 164, may affect the functions of the receptor. This study was conducted to investigate whether different polymorphisms of the beta(2)-AR are related to the treatment responses of an inhaled beta(2)-AR agonist in children with nocturnal and nonnocturnal asthma in Taiwan. Methods: The nocturnal asthma group consisted of 27 children (mean age of 10.3 +/- 2.4 years), and the nonnocturnal asthma group consisted of 24 patients (mean age of 9.9 +/- 3.0 years). Allele-specific polymerase chain reaction was performed to determine 16, 27, and 164 loci alleles of beta(2)-AR genetic polymorphisms, and peak expiratory flow (PEF) was measured before and 1 hour after inhalation of 0.2 mg/kg/dose of terbutaline to determine the treatment response in these patients. Results: The polymorphisms of beta(2)-AR 27 but not 16 or 164 were significantly associated with the response to terbutaline nebulizer (p < 0.05). The polymorphism of beta(2)-AR 16 was associated with nocturnal asthma (p = 0.027). The Gly16 allele was more prevalent in the nocturnal asthma group (9/27; 33.3%) than in the nonnocturnal asthma group (3/24; 12.5%). Arg16 allele was less prevalent in the nocturnal asthma (3/27; 11.1%) than in the nonnocturnal asthma group (10/24; 41.7%). There was also a linkage disequilibrium found between beta(2)-AR 16 (Arg/Arg) and beta(2)-AR 27 (Gln/Gln). Conclusion: These findings suggest that polymorphisms of beta(2)-AR 16 are related to nocturnal asthma and polymorphisms of beta(2)-AR 27 are associated with the variable responses to the inhaled terbutaline in children with nocturnal and nonnocturnal asthma. Copyright (C) 2011, Taiwan Pediatric Association. Published by Elsevier Taiwan LLC. All rights reserved.