Genetic association between common beta-2 adrenoreceptor polymorphism and asthma severity in school-age children

ADRB2 Gene Polymorphisms and Salbutamol Responsiveness in Serbian Children with Asthma

Inhaled β2 adrenergic receptor (β2-AR) agonists are the mainstay of asthma therapy. The β2-AR protein is encoded by the ADRB2 gene and variants within this gene can have significant consequences for modulating the response to asthma therapy. This cross-sectional study performed at the University Children’s Hospital in Belgrade, included 54 children with asthma. The subjects were genotyped for ADRB2 +46A>G (Arg16Gly, rs1042713) and +79C>G (Gln27Glu, rs 1042714) polymorphisms and the association with asthma severity and response to inhaled salbutamol was examined. In Serbian asthmatic children, allele +46A was detected with a frequency of 41.7% and allele +79G was detected with a frequency of 23.1%. Allele +46G was found to be associated with a better response to inhaled salbutamol (p <0.05) and with mild form of asthma (p <0.05). Polymorphism ADRB2 +46A>G may be a determinant of asthma severity and response to salbutamol in children with asthma. We did not find any association of +79C>G polymorphisms with the asthma severity and bronchodilator response to inhaled salbutamol. The results of this study can be potentially useful for personalization of asthma treatment.

Beta 2 Adrenergic Receptor Genetic Polymorphisms in Bronchial Asthma: Relationship to Disease Risk, Severity, and Treatment Response

BACKGROUND

The β₂-adrenergic receptor gene is one of the most extensively studied genes with respect to asthma prevalence and severity. The Arg16Gly and Gln27Glu polymorphisms in the β₂-adrenergic receptor gene cause changes in the amino acids sequence of the receptor which may cause alteration in response to bronchodilators and the risk of asthma.

OBJECTIVE

The purpose of the study was to determine the association between β₂-adrenergic receptor gene polymorphisms and asthma risk, severity and response to therapy.

SUBJECTS AND METHODS

58 asthmatic patients and 38 healthy subjects were included. The β₂-adrenergic receptor polymorphisms genotyping was done using Real-Time polymerase chain reaction.

RESULTS

The allelic frequencies for the Arg16Gly polymorphism were 15.5%, 48.3%, and 36.2% for the homozygous A wild, heterozygous, and homozygous G mutant alleles in asthmatics (P < 0.01) and 5.3%, 47.4%, and 47.4% in healthy subjects (P < 0.01). For the Gln27Glu polymorphism, the allelic frequencies for the homozygous C wild, heterozygous and homozygous G mutant alleles were 51.7%, 41.4%, and 6.9% in asthmatics (P < 0.01) and 44.7%, 39.5%, and 15.8% in healthy subjects (P < 0.01). The heterozygous Arg16Gly and Gln27Glu were found in most of severe asthma cases (7/13, 53.8% each). While homozygous wild and mutant seemed to be protective and associated with mild disease in both alleles. Finally, 75% of Arg16Gly heterozygous group were good responders (P < 0.01), 81% of homozygous G mutant were bad responders. For Gln27Glu polymorphism, 60% of C wild group were good responders and 75% of G mutant group were bad responders.

CONCLUSIONS

The findings suggest that the Arg16Gly and Gln27Glu polymorphisms in the β2-AR gene are associated with asthma severity and response to therapy and might be used in personalized treatment for these patients in the future. This work is registered in ClinicalTrial.gov with ID: NCT03118869.

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.

SPINK5 and ADRB2 haplotypes are risk factors for asthma in Mexican pediatric patients

BACKGROUND

Asthma is one of the most common respiratory diseases worldwide, and the complexity of its etiology has been widely documented. Chromosome 5q31-33 is one of the main loci implicated in asthma and asthma-related traits. IL13, CD14 and ADRB2, which are located in this risk locus, are among the genes most strongly associated with asthma susceptibility.

OBJECTIVES

This study evaluated whether single-nucleotide polymorphisms or haplotypes at 5q31-33 conferred risk for asthma in Mexican-Mestizo pediatric patients.

METHODS

We performed a case-controlled study including 851 individuals, 421 of them affected with childhood-onset asthma and 430 ethnically matched unaffected subjects. We used the TaqMan Allelic Discrimination Assay to genotype 20 single-nucleotide polymorphisms within IL5, RAD50, IL13, IL4, CD14, SPINK5, HTR4, ADRB2 and IL12B.

RESULTS

Although no association was detected for any risk allele, three SPINK5 haplotypes (GGCT: p = 6 × 10(-6); AATC: p = 0.0001; AGTT: p = 0.0001) and five ADRB2 haplotypes (AGGACC: p = 0.0014; AGGAAG: p = 0.0002; TGAGAG: p = 0.0001; AGGAAC: p = 0.0002; AAGGAG: p = 0.003) were associated with asthma. Notably, the AGTT SPINK5 haplotype exhibited a male gender-dependent association (p = 7.6 × 10(-5)).

CONCLUSION

Our results suggest that SPINK5 and ADRB2 haplotypes might play a role in the susceptibility to childhood-onset asthma.