Department of Internal Medicine, King Fahad Hospital of the University, College of Medicine, University of Dammam, Dammam, Saudi Arabia.
Ann Thorac Med. 2011 Apr;6(2):66-9. doi: 10.4103/1817-1737.78416.
Two polymorphisms of beta(2)-adrenergic receptor (β(2)-AR) gene, namely the substitution from arginine (Arg) to glycine (Gly) at codon 16 and from glutamine (Gln) to glutamic (Glu) at codon 27, are linked with functional changes in the β(2)-AR in the respiratory system even though they are not deemed to be susceptibility genes for asthma per se. The objective of this study was to investigate this association in a subset of asthmatic patients, namely those with nocturnal asthma.
The β(2)-AR gene polymorphisms at codon 16 and 27 were assessed in 40 patients clinically diagnosed with nocturnal asthma and 96 normal controls. Genomic DNA was obtained from whole blood and genotyping was carried out by a PCR based restriction fragment length polymorphism technique.
There was a statistically significant difference in genotype frequencies at codon 16 (Arg/Gly) between nocturnal asthmatic patients and normal control subjects (P < 0.05). However, there was no statistically significant difference in allele frequencies between the two groups. In addition, there was a significant association between Arg16-Gly genotype with nocturnal asthma compared to homozygous Gly16 (codominant model P = 0.0033, OR = 3.69: 95% CI: 1.49-9.12). However, there were no statistically significant differences in genotype and allele frequencies at codon 27 (Gln/Glu) between the normal control and nocturnal asthmatic groups (χ(2) = 1.81, P = 0.41). The results also indicate that linkage disequilibrium existed between the β(2)-AR codon 16 and β(2)-AR codon 27 polymorphism (|D´| = 0.577). The data for all haplotypes did not show a statistically significant association.
We present the genotype and allele frequencies of β(2)-AR gene polymorphisms in normal Saudi subjects and nocturnal asthmatic patients. There was a significant difference in genotype frequencies at codon 16 (Arg/Gly). However, our study indicates a poor association of individual single nuceotide polymorphisms with nocturnal asthma.
β2-肾上腺素能受体（β2-AR）基因的两个多态性，即密码子 16 处从精氨酸（Arg）变为甘氨酸（Gly）和密码子 27 处从谷氨酰胺（Gln）变为谷氨酸（Glu），与呼吸系统中β2-AR 的功能变化有关，尽管它们本身并不被认为是哮喘的易感基因。本研究的目的是在一组哮喘患者中，即那些有夜间哮喘的患者中，研究这种相关性。
对 40 例临床诊断为夜间哮喘的患者和 96 例正常对照者的β2-AR 基因密码子 16 和 27 的多态性进行评估。从全血中提取基因组 DNA，并通过基于 PCR 的限制性片段长度多态性技术进行基因分型。
夜间哮喘患者和正常对照组在密码子 16（Arg/Gly）的基因型频率上有统计学差异（P < 0.05）。然而，两组之间的等位基因频率没有统计学差异。此外，Arg16-Gly 基因型与夜间哮喘的相关性显著，与纯合 Gly16 相比（共显性模型 P = 0.0033，OR = 3.69：95%CI：1.49-9.12）。然而，正常对照组和夜间哮喘组之间在密码子 27（Gln/Glu）的基因型和等位基因频率上没有统计学差异（χ2 = 1.81，P = 0.41）。结果还表明，β2-AR 密码子 16 和β2-AR 密码子 27 多态性之间存在连锁不平衡（|D´| = 0.577）。所有单倍型的数据没有显示出统计学上的显著相关性。
我们提供了β2-AR 基因多态性在正常沙特人和夜间哮喘患者中的基因型和等位基因频率。密码子 16（Arg/Gly）的基因型频率有显著差异。然而，我们的研究表明，单个核苷酸多态性与夜间哮喘的相关性较差。
