Association of A/T Polymorphism of the CHRM2 Gene with Bronchodilator Response to Ipratropium Bromide in Asthmatic Children

Introduction: The aim of this study was to analyze the possible association of A/T polymorphism of the CHRM2 gene with asthma, and pharmacogenetic analysis of the polymorphism with bronchodilator response to ipratropium bromide, an anticholinergic drug used in asthma. Material and methods: Analysis was performed in a group of 113 children diagnosed with bronchial asthma, and in a group of 123 healthy children from a control group. Moreover, in the group of 32 asthmatic children without concurrent treatment with long-acting β₂-agonists, bronchodilator response to ipratropium bromide was evaluated by the spirometric lung function test. Genetic analysis was performed for A/T polymorphism (rs6962027) of the CHRM2 gene. Genotyping was done with the PCR-RFLP method. Statistical analysis was performed using Statistica v.7.1 software. Results: No association of A/T polymorphism was found with asthma (p = 0.865 for genotypes and p = 0.782 for alleles). In the pharmacogenetic analysis, it was observed that patients carrying TT genotype of CHRM2 gene polymorphism demonstrated significantly poorer response to anticholinergic drug as compared to the patients with other genotypes for this polymorphism (p = 0.035). Conclusions: We found that TT genotype in the CHRM2 gene was associated with poor bronchodilator response in asthmatic patients. The results should be analyzed carefully considering the small sample size and should be confirmed by other research groups.