Association among ORMDL3 gene expression, 17q21 polymorphism and response to treatment with inhaled corticosteroids in children with asthma.

Recent genome-wide association studies linked childhood asthma with single-nucleotide polymorphisms (SNPs) in ORM1-like protein 3 (ORMDL3) gene region on chromosome 17q21. We analyzed the effect of functional SNP rs2872507 in ORMDL3 gene region on the response to antiasthmatic treatment with inhaled corticosteroids (ICSs) and ORMDL3 gene expression. Forced expiratory volume in 1 s increased significantly by 13.3% of predicted value after therapy in atopic asthmatics with AA genotype, compared with 7.0% in heterozygotes and 4.9% increase in GG homozygotes (P=0.0176). Median relative expression of ORMDL3 gene in asthmatics with AA, AG and GG genotypes was 0.75, 1.05 and 1.21, respectively (P<0.0001). Treatment with ICSs was significantly associated with the increase of median relative expression of ORMDL3 gene, from 0.88 to 1.21 (P=0.0032) in atopic asthmatics. Our results suggest that rs2872507 is associated with ORMDL3 gene expression and with ICS treatment response in children with atopic asthma.