Polymorphic Genes of Xenobiotic-Metabolizing Enzymes Associated with Predisposition to Bronchial Asthma in Hereditarily Burdened and Nonburdened Children

The frequencies of theCYP1A1valine allele, homozygous deletions of GSTM1 and GSTT1, and two point mutations of the NAT2 gene, NAT2: S1(C⁴⁸¹ T) and S2 (G⁵⁹⁰ A), were compared in healthy children and children having bronchial asthma. The S1 mutation was associated with resistance, and all of the other traits, with predisposition to the disease. In families of patients with diseased progenitors and in those with healthy progenitors, the estimates of the asthma risk were similar. In both groups, parameters of the trait association with the disease depended on passive smoking. At passive smoking, a trend to an overrepresentation (high odds ratio, OR) of the GSTM1 null genotype and S2 mutation of theNAT2 gene was observed, whereas the odds ratio of the GSTT1 null genotype decreased, and those of the CYP1A1 and S1 mutation of the NAT2 gene remained unchanged. The highest OR = 36.25 (P < 0.01) was characteristic of theGSTT1 null genotype in nonsmoking hereditary burdened patients. The results obtained suggest an important role of xenobiotic-metabolizing enzymes in development of bronchial asthma.