Genetic associations of the response to inhaled corticosteroids in children during an asthma exacerbation

Background: Genetic associations of the response to inhaled corticosteroids (ICSs) during an asthma exacerbation are unknown.

Objective: To evaluate the role of genetic variants in the therapeutic response to high-dose ICS in children with moderate-to-severe asthma exacerbations.

Methods: Eighty-two children (56 boys/26 girls, mean age 9.6 ± 3.2 years) with moderate-severe asthma exacerbation were genotyped for eight single-nucleotide polymorphisms that were a priori associated with ICS response in chronic asthma treatment: glucocorticosteroid receptor (NR3C1) rs41423247; corticotrophin-releasing hormone receptor1 (CRHR1) rs242939, rs242941, and rs1876828; T-box 21 (TBX21) rs2240017; glucocorticoid-induced transcript 1 (GLCCl1); and T gene rs3099266 and rs2305089. Children were treated with a single high-dose (4000 μg) fluticasone propionate given by a nebulizer followed by 1000 μg/day of inhaled fluticasone propionate for 6 days. Primary outcome measure was the improvement in FEV1 at 4 h.

Results: Mean FEV1 was 71.7 ± 14.2% at presentation. Overall, fluticasone treatment resulted in a significant improvement in asthma score and FEV1 (p < 0.0001 for both). Children with the GG genotype at NR3C1 rs41423247 (n = 26) had a higher improvement in FEV1 [24.2% (interquartile range 11.5-36.3)] compared to those with CG+CC (n = 19), [7.9% (interquartile range 6.1-24.6) (p = 0.006)].

Conclusion: Homozygosity for the G allele at rs41423247 of the glucocorticosteroid receptor (NR3C1) gene is associated with a higher improvement in FEV1 at 4 h in children with moderate-to-severe asthma exacerbation treated with high-dose ICS. This observation may have important clinical implications especially for children who use systemic steroids frequently for recurrent asthma exacerbations.