Background: Diverse factors, including gene polymorphism, influence the development of asthma
predisposing an individual to atopy and airway hyper-responsiveness.
Objective: To explore the contribution of beta-2 adrenergic receptor (β2-AR) gene polymorphisms
(Arg16Gly and Gln27Glu) to the risk and severity of adult bronchial asthma in Egypt.
Subjects and Methods: This study was included 75 Egyptian subjects divided into: Group I: 50
bronchial asthma patients subdivided into mild, moderate and severe asthma. Group II: 25 apparently
healthy controls. Full history taking, physical examination, plain chest x-ray, pulmonary function
tests, and laboratory investigations were performed. Serum IgE was estimated by ELISA. Detection
of Arg16Gly and Gln27Glu polymorphisms was performed by PCR-based RFLP using fast-digest
NcoI and BbvI restriction enzymes, respectively.
Results: Non-significant differences in Arg16Gly genotype and allele frequencies were found in
asthmatics versus controls. There was significant increased Gln/Gln genotype and Gln allele but
significant decreased Gln/Glu genotype of Gln27Glu in asthmatics versus controls. Combined
haplotypes showed significant increased Arg16Arg-Gln27Gln but significant decreased Gly16GlyGlu27Gln in asthmatics versus controls. As regard severity, there were significant increased Gln/Gln
and 16Arg/Arg-27Gln/Gln in severe asthma (risk factors) while Glu/Glu was significantly decreased
(protective). There was also significant increased 16Arg/Gly-27Glu/Glu haplotype in mild asthma
and significant increased 16Gly/Gly-27Glu/Gln haplotype in moderate asthma (both protect against
severity).
Conclusion: The isolated β2-AR Gln27Glu polymorphism and the combined Gln27Glu and
Arg16Gly haplotypes but not the isolated Arg16Gly polymorphism might contribute to asthma risk
and grades of severity