SNP genotyping
asthma
ASTHMA, POSITIVE
SNP genotyping was performed using DNA isolated from whole blood (QIAamp DNA Blood Mini Kit, Qiagen) using TaqMan™ SNP genotyping assays (Thermo Fisher Scientific) on a StepOne Real-Time PCR System (StepOne software v.2.3; Applied Biosystems). Positive control DNA was purchased from Coriell Institute for Medical Research (Catalogue#: HG00103, HG00581, HG00654).The unweighted genetic risk score (GRS) was calculated from 12 single nucleotide polymorphisms (SNPs) risk alleles. The SNPs were chosen based on significant associations with air pollution and asthma development or severity in gene candidate studies or due to in vitro evidence of their increased activation by pollution particulates 