Association between β2-Adrenergic Receptor Genetic Polymorphisms and Nocturnal Asthmatic Patients of Chinese Han Nationality

Abstract

Background: As a result of the finding that the mutation of Arg into Gly at β₂-adrenergic receptor (β₂-AR)16 loci could promote the downregulation effect triggered by the β₂-agonist, it was supposed that Gly16 might be associated with the downregulation of β₂-AR in patients with nocturnal asthma. Objective: It was the aim of this study to analyze the association between β₂-AR genetic polymorphisms and nocturnal asthmatic patients of Chinese Han nationality. Methods: A polymerase chain reaction allele-specific oligonucleotide hybridization assay was used to determine 16 and 27 loci alleles of β₂-AR genetic polymorphisms in 25 nocturnal asthmatic patients (nocturnal asthma group), 22 non-nocturnal asthmatic patients (non-nocturnal asthma group), and 72 healthy people (control group). All people investigated were of Chinese Han nationality. Results: The distribution frequency of genotype Arg/Arg, Arg/Gly, and Gly/Gly at β₂-AR 16 loci was 12, 16 and 72% in the nocturnal asthma group; and 27, 41 and 32% in the non-nocturnal asthma group. There was a significant increase in the frequency of genotype Gly/Gly and allele Gly in the nocturnal asthma group compared with the non-nocturnal asthma group (p < 0.01). However, there was no significant difference in the frequency of genotype Gly/Gly and allele Gly in the non-nocturnal asthma group, compared with the control group. There was no significance in the frequency of the genotypes and alleles of β₂-AR 27 loci among the three groups (p > 0.05). Conclusion: The Gly16 polymorphism of β₂-AR was overrepresented in nocturnal asthmatic patients, correlated with nocturnal asthma, and therefore appeared to be an important genetic factor in the expression of this asthmatic phenotype.