RESUMO
<p><b>OBJECTIVE</b>To 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.</p><p><b>METHODS</b>Polymerase 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.</p><p><b>RESULTS</b>The 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).</p><p><b>CONCLUSIONS</b>Genotype DD of ACE is related to genetic susceptibility to childhood asthma and may be the risk factor for childhood asthma.</p>