Association of the miR-196a2, miR-146a, and miR-499 Polymorphisms with Asthma Phenotypes in a Korean Population

Background MicroRNAs (miRNAs) modulate expressions of inflammatory genes, thereby regulating inflammatory responses. Single nucleotide polymorphisms (SNPs) in miRNAs could affect their efficiency in binding to messenger RNAs (mRNAs). Objective We investigated the associations of miRNA SNPs with asthma phenotypes. miR-196a2 (rs11614913 T>C), miR-146a (rs2910164 C>G), and miR-499 (rs3746444 A>G) were genotyped in 347 asthma patients and 172 normal healthy controls (NCs). Results The CT/CC genotype of miR-196a2 rs11614913 was associated with eosinophilic asthma ( p = 0.004) and a higher sputum eosinophil count compared with the TT genotype ( p = 0.003). The CG/GG genotype of miR-146a rs2910164 tended to be associated with higher bronchial hyperresponsiveness to methacholine (PC 20 ) compared with the CC genotype. The AG/GG genotype of miR-499 rs3746444 was associated with higher predicted values of forced expiratory volume in 1 s (%FEV 1 ) compared with the AA genotype ( p = 0.008). Conclusions Genetic polymorphisms in miR-196a2 , miR-146a , and miR-499 could be potential biomarkers for asthma phenotypes and targets for asthma treatments in a Korean population.