The effect of BclI polymorphism of NR3C1 gene on asthma phenotypes in Egyptian children

Abstract

Background: BclI is the promoter polymorphism observed within human glucocorticoid receptor gene (hGR/NR3C1) which plays an important role in the development of bronchial asthma (BA) and resistance to Glucocorticosteroids (GCs) in the severe BA. Objective: To assess the influence of BclI gene (rs41423247) polymorphisms on phenotypic expression of bronchial asthma in a group of Egyptian asthmatic children. Methods: This case control study included 135 asthmatic children with varying degrees of asthma severity. They were recruited from Allergy and Pulmonology Outpatient Clinic, Cairo University. Ninety healthy age and sex matched children served as the control group. Determination of BclI single nucleotide polymorphism (SNP) was done by polymerase chain reaction restriction fragment length polymorphism (PCR- RFLP). Results: Our results revealed that the variants of BclI polymorphism: CC/CG/GG was found with frequency 73.3%, 26.7%, 0% in control group. While in asthmatic children, their frequency was 42.2%, 51.1%, 6.7%, respectively. This revealed a significant difference in distribution between cases and control, similarly there was a significant difference in frequency of allele G between both groups (P-value <0.001). The frequency of allele G/C showed statistically significance association with increased severity of bronchial asthma (P-value<0.001), with uncontrolled asthma and hospitalization (P value <0.001). Conclusion: The Bcl I polymorphism of hGR/NR3C1 gene is significantly associated with bronchial asthma. The GG phenotype is significantly associated with increased susceptibility to the development of severe asthma and uncontrolled asthma symptoms, with increased risk of hospitalization.