Lack of association of atopy/asthma and the interleukin-4 receptor alpha gene in Japanese.

ABSTRACT

BACKGROUND: Susceptibility to the development of atopic diseases is known to involve genetic factors. Several investigators have reported the interleukin-4 (IL-4) receptor alpha gene to be involved in the development of atopy. Recent study has shown that the R allele of a polymorphism in the IL-4 receptor alpha chain gene (Q576R) to be associated with atopy. OBJECTIVE: The objective of this study was to evaluate the possible role of the IL-4 receptor alpha gene in modulating allergic response and asthma in the Japanese population. METHODS: We conducted linkage analysis using microsatellite markers flanking the IL-4 alpha receptor gene in 82 families ascertained through asthmatic children. The IL-4 receptor Q576R polymorphism was also genotyped by PCR-restriction fragment length polymorphism analysis. RESULTS: We did not find evidence for linkage of the asthma and atopy phenotypes with the markers D16S298 and D16S403 (P = 0.10 and P = 0.56, respectively, for the atopy phenotype and P = 0.17 and P = 0.60, respectively, for the asthma phenotype). The IL-4 receptor R576 allele was not preferentially transmitted to atopy- or asthma-affected children (chi2 = 1.67, P = 0.24 for atopy and chi2 = 0.91, P = 0.40 for asthma). In addition, the prevalence of the R576 allele among parents with and without atopy was similar, 20 of 81 (24.7%) parents with atopy and 22 of 77 (28.6%) parents without atopy. CONCLUSION: Our findings indicate that the IL-4 receptor alpha gene does not exert a substantial influence on the inheritance of atopy or asthma in this Japanese population.