A Pilot Study of Polymorphism of Adrenergic Beta-2 Receptor and Mild Asthma: A Clinical and Pharmacogenetic Study

Glycine allele at codon 16 has previously been associated with the increase in asthma severity, bronchial hyperresponsiveness and also the increase in inhaled corticosteroid dependence. This study was designed to evaluate the genetic alleles in mild asthma. Thirty-four patients with diagnosis of mild asthma (FEV1 ≥ 80%, positive methacholine test) and body mass index (BMI ≤ 30 Kg/m2) were included in the study. They could only use short acting beta-2 agonists for asthma control. Smoking, infection, occupational sensitizers’ exposure, gastroesophageal reflux, diabetes mellitus and heart failure were also considered as exclusion criteria. All patients were genotyped at 16th and 27th codons. Among all, 20 (58.8%) Arg/Gly, 14 (41.2%) Arg/Arg and no Gly/Gly genotype were detected at codon 16. Genotyping at codon 27 revealed 2 (5.9%) Glu/Glu, 13 (38.2%) Glu/Gln and 18 Gln/Gln (52.9%). Based on the obtained results, Arg/Gly mutation had a higher rate among the studied subjects compared to Arg/Arg polymorphism. This is a pilot study which shows a probable usefulness of genotyping for predicting of asthma severity.