Aim: To discover the role of beta2-adrenergic receptor (beta2-AR) polymorphism on the response to beta-2 agonist, particularly in coding amino acid at sequences 16 and 27 as well as adjacent nucleotides.
Methods: The study was conducted by nested case-control method with consecutive samples of asthma patients aged 15-60 years at the outpatient clinic, Department of Pulmonology in Dr. Wahidin Sudirohusodo General Hospital, Makassar. Twenty-eight patients were found irresponsive to terbutaline nebulation (increased FEV1 < 15%) and 56 patients were responsive (increased FEV1 > or =15%). DNA extraction and amplification were performed by PCR as well as polymorphism detection, which was done by automatic sequencing machine.
Results: The Arg 16 polymorphism did not have any effect on the response to terbutaline nebulation, but Gln 27 polymorphism did with OR 3.18. New polymorphism was found in nucleotide at 20th order before the start codon, it was T/C -20, which also has an effect on the response to terbutaline nebulation with OR 4.53. When the three polymorphisms were combined, the effect were greater with OR 11.11. It was found that age, gender, obesity, onset and ethnicity had no effect on the response to terbutaline nebulation.
Conclusion: Polymorphism of the novel Gln 27 and T/C -20 (newly known) have an effect on the response to beta-2 agonist. Both combination and polymorphism of Arg 16 will bring greater effect on the response to beta-2 agonist.