Beta 2-adrenergic polymorphisms and total serum IgE levels in children with asthma from Argentina

B2 adrenergic receptor gene polymorphism effect on childhood asthma severity and response to treatment

BackgroundAlterations of B2 adrenergic receptor (β₂AR) can modulate the severity of asthma and the response to treatment. Therefore, we aimed to evaluate β₂AR gene polymorphism at codons 16 and 27 and their effect on asthma severity and response to treatment in asthmatic children.MethodsCase-control study was conducted on 156 children; 104 of them had bronchial asthma and 52 were healthy children (control group). Subjects of the study underwent history taking, clinical examination, pulmonary function tests, serum IgE level assessment, and identification of β₂AR-16 A46G and β₂AR-27 C79G polymorphism using PCR-Restriction Fragment length polymorphisms (RFLP) test.ResultsThere was a higher frequency of Arg-Gly genotypes (odds ratio (OR)=6.57; confidence interval (CI): 2.42-18.81, P<0.001) and lower frequency of Arg-Arg (OR=4.7; CI: 2.05-10.95, P<0.001) among asthmatic children compared with that among controls at codon 16. The presence or absence of Gly16 or Glu27 either homozygous or heterozygous for both correlated with the grade of asthma severity. The presence of heterozygous Arg-Gly and Gln-Glu gives a better response to drug therapy than the presence of Gly-Gly and Glu-Glu genotypes at codons 16 and 27.ConclusionPolymorphism of β₂AR at codons 16 and 27 correlates with asthma severity and response to treatment in asthmatic children.

β(2) -adrenoreceptor polymorphisms in asthmatic and non-asthmatic schoolchildren from Colombia and their relationship to treatment response

Asthma is a chronic and recurrent disease. Its high prevalence around the world is the result of a complex interaction between genetic and environmental factors. The genetic aspects of susceptibility, severity, and response to treatment in asthma are of great scientific interest. The purpose of the study was to establish the relationship between the Gln27Glu and Arg16Gly alleles of the β(2) -adrenergic receptor (ADRB2) gene with respect to the susceptibility to and severity of asthma, as well as the response to treatment in mestizo schoolchildren. 109 schoolchildren with asthma diagnosis and 137 asymptomatic controls were genotyped for the Arg16Gly and Gln27Glu alleles of the ADRB2 gene by minisequencing. Allele, genotype, and haplotype frequencies of the ADRB2 gene between asthmatic and non-asthmatic as well as demographic, clinical, and spirometric variables among asthmatic patients according to their genotype were compared. ADRB2 gene expression was determined by real-time quantitative PCR. No statistical differences were found in allele, genotype, and haplotype frequencies of the ADRB2 gene between cases and controls. We did not find differences between asthmatic patients classified according to their ADRB2 genotypes and haplotypes when evaluating demographic, clinical, and spirometric variables. The ADRB2 genotype and haplotype are not associated with spirometric responses or ADRB2 gene expression after administration of a β-(2) agonist plus a glucocorticoid. These results suggest that in the group of mestizo schoolchildren studied, the Arg16Gly and Gln27Glu polymorphisms are not markers of susceptibility or severity of asthma and do not affect ADRB2 gene expression during the rescue therapy.

Association of β(2)-adrenergic receptor polymorphisms with asthma in a North Indian population

BACKGROUND

β(2)-Adrenergic receptor (β(2)AR), a G-protein coupled receptor, is present on the bronchial smooth muscle cells and results in bronchodilation upon activation. The genetic factors determining β(2)AR expression and function may not only alter the response of an individual to the therapy but also may serve as predictive markers for response to the agonists used in the therapy. The present study aimed at evaluating the role of β(2)AR-16 and β(2)AR-27 gene polymorphisms in asthma.

METHODS

A case-control study was performed with a total of 824 adult subjects, including 410 asthmatics and 414 healthy controls from regions of North India. The β(2)AR-16 and β(2)AR-27 polymorphisms were genotyped by PCR-RFLP.

RESULTS

Statistical analysis for the β(2)AR-16 polymorphism revealed that the mutant Gly16 allele was significantly associated with asthma, with OR = 0.80, 95 % CI = 0.65-0.99, and P = 0.032. The Gly16/Gly16 mutant genotype also confers decreased risk toward asthma, with OR = 0.65, 95 % CI = 0.41-1.02, and P = 0.049. However, the β(2)AR-27 polymorphism was not associated with asthma as it did not reach statistical significance, with OR = 0.86, 95 % CI = 0.69-1.07, and P = 0.163.

CONCLUSION

The β(2)AR-16 polymorphism confers a decreased risk toward asthma while the β(2)AR-27 polymorphism is not associated with asthma in the studied North Indian population.