B2 adrenergic receptor gene polymorphism effect on childhood asthma severity and response to treatment

BACKGROUND: Alterations of B-2 adrenergic receptor (beta 2AR) can modulate the severity of asthma and the response to treatment. Therefore, we aimed to evaluate beta 2AR gene polymorphism at codons 16 and 27 and their effect on asthma severity and response to treatment in asthmatic children. METHODS: Case-control study was conducted on 156 children; 104 of them had bronchial asthma and 52 were healthy children (control group). Subjects of the study underwent history taking, clinical examination, pulmonary function tests, serum IgE level assessment, and identification of beta 2AR-16 A46G and beta 2AR-27 C79G polymorphism using PCR-Restriction Fragment length polymorphisms (RFLP) test. RESULTS: There was a higher frequency of Arg-Gly genotypes (odds ratio (OR) = 6.57; confidence interval (CI): 2.42-18.81, P < 0.001) and lower frequency of Arg-Arg (OR = 4.7; CI: 2.05-10.95, P < 0.001) among asthmatic children compared with that among controls at codon 16. The presence or absence of Gly16 or Glu27 either homozygous or heterozygous for both correlated with the grade of asthma severity. The presence of heterozygous Arg-Gly and Gln-Glu gives a better response to drug therapy than the presence of Gly-Gly and Glu-Glu genotypes at codons 16 and 27. CONCLUSION: Polymorphism of beta 2AR at codons 16 and 27 correlates with asthma severity and response to treatment in asthmatic children.