Beta 2 Adrenoceptor Polymorphism and Response to Salbutamol in Asthmatics of Punjabi Origin in Islamabad

Objectives: To associate single nucleotide polymorphism of adrenoceptor beta2 gene (Arg16Gly rs 1042713) with bronchial asthma in patients of Punjabi ethnicity in Islamabad and to compare pharmacogenetic aspect by salbutamol responsiveness in asthmatics with and without single nucleotide polymorphism of adrenoceptor beta2 gene (Arg16Gly rs 1042713). Methodology: This cross-sectional study was conducted in Physiology department of Al-Nafees Medical College & Hospital Islamabad in collaboration with Islamabad Diagnostic Center and COMSATS University Islamabad from January 2021 to June 2022. A total of 289 asthmatics and 289 non-asthmatics were enrolled. Genotype was done by Restriction Fragment Length Polymorphism-Polymerase Chain Reaction (RFLP-PCR) method. Salbutamol responsiveness was done based on symptomatic improvement by bronchial Asthma Control Test (ACT) of Global Initiative for Asthma (GINA). Results: Risk estimation calculations between asthmatics and non-asthmatics showed no association with polymorphism as depicted by nonsignificant chi square p value (0.9), odds ratio (95% confidence interval); OR (CI); 0.98 (0.70-1.33) and chi square p value (0.8), OR (CI); 1.0 (0.71-1.51) in dominant and recessive model respectively. Salbutamol responsiveness revealed strong association with AA genotype as reflected by highly significant chi square p value 0.0001, OR (CI); 7.5 (4.1-13.7) between AA vs AG and chi square p value 0.0001, OR (CI); 8.4 (4.2-16.8) between AA vs GG respectively. Conclusions: There was no evidence of association of single nucleotide polymorphism of adrenoceptor beta2 gene (Arg16Gly rs 1042713) with bronchial asthma in Punjabi ethnics of Islamabad. Comparison of salbutamol responsiveness revealed AA homozygotes better responders than AG and GG carriers.