β2-Adrenergic Receptor Polymorphisms Affect Airway Responsiveness to Salbutamol in Asthmatics

We examined the β-adrenergic receptor (β₂AR) polymorphisms (Arg16 → Gly, Gln27 → Glu) and clinical status for 117 asthmatics. Airway responsiveness to methacholine and β₂-agonists was evaluated with Astograph®. The atopic factors, pulmonary function test, and airway responsiveness to methacholine did not differ significantly among the different β₂AR genotypes. Asthmatics homozygous for Glyl 6 showed significantly lower airway responsiveness to inhaled salbutamol than those heterozygous for Arg/Gly16 or homozygous for Arg16. Asthmatics heterozygous for Gln/Glu27 had significantly later asthma onsets than those homozygous for Gln27. These results suggest that β₂AR polymorphisms play an important role in the airway responsiveness to inhaled β₂- agonist and the initial asthma onset.