OBJECTIVETo analyze the frequency distribution of single nucleotide polymorphisms (SNPs) of four asthma-related gene loci (ACE I/D; ADRB2 Arg16Gly; TNF-α G-308A; MS4A2 Glu237Gly) in 198 asthmatic children, and to investigate its association with genetic susceptibility to childhood asthma and some clinical phenotypes of asthma.

METHODSPolymerase chain reaction product electrophoresis identification and real-time quantitative PCR detecting system were used to determine the frequency distributions of the SNPs of the four asthma-related gene loci in 198 asthmatic children and 110 healthy controls. The serum total IgE (TIgE) levels and blood eosinophil proportion (%EOS) of the asthmatic children were measured. Different genotypes at the four asthma-related gene loci were compared in terms of TIgE and %EOS.

RESULTSThe genotype DD of angiotensin-converting enzyme (ACE) had a significantly higher frequency in the asthmatic children than in the healthy controls (χ2= 30.667, P<0.01), and the frequency of D allele was also significantly higher in the asthmatic children than in the healthy controls (χ2=7.151, P<0.01). No correlation was found between the polymorphism of each gene locus and serum TIgE level and %EOS (P>0.05).

CONCLUSIONSGenotype DD of ACE is related to genetic susceptibility to childhood asthma and may be the risk factor for childhood asthma.