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The synergistic effects of the IL‐9 gene and environmental exposures on asthmatic Taiwanese families as determined by the transmission/disequilibrium test
Author(s) -
Wang TN.,
Chen WY.,
Huang YF.,
Shih NH.,
Feng WW.,
Tseng HI.,
Lee CH.,
Ko YC.
Publication year - 2006
Publication title -
international journal of immunogenetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.41
H-Index - 47
eISSN - 1744-313X
pISSN - 1744-3121
DOI - 10.1111/j.1744-313x.2006.00578.x
Subject(s) - transmission disequilibrium test , allele , asthma , offspring , atopy , immunology , odds ratio , biology , genetics , allergy , genotype , proband , gene , medicine , haplotype , pregnancy , mutation
Summary Asthma occurs in genetically susceptible individuals in the presence of environmental factors. The interleukin‐9 (IL‐9) gene, one of the cytokine genes located on chromosome 5q31, plays an important role in the development of asthmatic syndrome by enhancing both T‐cell and mast‐cell function. This study investigated GT repeat polymorphism of the IL‐9 gene and the gene–environment interactions, which may predispose individuals to asthma and atopy pathogenesis. In this study, we used the transmission/disequilibrium test (TDT) to investigate the relationship between asthma and the IL‐9 gene by studying 123 parent–offspring trios and 91 siblings. For allele‐specific TDT chi‐squared test, allele 122 of the IL‐9 gene showed significant association with asthmatics with specific IgE against house dust (HD) ( P = 0.038). The additions of covariates to TDT to conduct the synergistic effects between the IL‐9 gene and environmental factors into account were estimated by conditional logistic regression models. The odds ratio for transmission of allele 122 of the IL‐9 gene was 1.23 ( P = 0.28) for all asthmatic probands. There was slight increased interaction effect on asthma between transmission of allele 122 of IL‐9 gene to offspring and who were exposed to the fur of pets (OR = 3.33, P = 0.047). We also detected elevated odds of transmission of allele 122 to atopic asthmatic probands (OR = 2.08, P = 0.03) and offspring with very high levels of serum IgE (≥ 800 IU mL −1 ). In conclusion, this study has found that the IL‐9 gene was slightly associated with asthmatics who have positive specific IgE against Der p (or Der f) and house dust, when information on environmental factors was incorporated as effect modifiers.