Association of interferon-gamma and interferon regulatory factor 1 polymorphisms with asthma in a family-based association study in Taiwan.
BACKGROUND
Asthma is a multi-factorial disorder caused by complex interactions between genetic and environmental factors. IFN-gamma and IFN regulatory factor 1 (IRF-1) affect Th1/Th2 cytokine balance, and influence the differentiation of Th2 cells, which influence the development of asthma.


OBJECTIVE
This study investigated CA repeats polymorphism of the IFN-gamma gene and GT repeats polymorphism of the IRF-1 gene, which may predispose individuals to asthma pathogenesis.


METHODS
In the present study, we used the transmission/disequilibrium test (TDT) to investigate the relationship between asthma and the IFN-gamma and IRF-1 polymorphisms by studying 348 subjects composed of 232 parents and 116 asthmatic children.


RESULTS
For global TDT test, IFN-gamma CA repeats and IRF-1 GT repeat polymorphisms showed a significant association with asthma in children (P=0.009 and 0.017, respectively). We demonstrated that 13 CA repeats (138 bp) of IFN-gamma gene and 11 GT repeats (306 bp) of IRF-1 gene are significantly preferentially transmitted to asthmatic children (T/NT=89/61, chi2=8.43, P<0.005 and T/NT=75/49, chi2=8.18, P<0.005, respectively). The offspring will have an increased risk of asthma when their parents transmit IFN-gamma 13 CA repeats (OR=1.83, P=0.009) and IRF1 11 GT repeats (OR=1.88, P=0.007) to them. But we observed that the IFN-gamma and IRF-1 polymorphisms are not associated with IgE concentrations.


CONCLUSIONS
These findings provide strong evidence of which IFN-gamma CA repeat and IRF-1 GT repeat polymorphisms influence the risk of asthma for children in Taiwan.
Wang
T-N
TN
Faculty of Public Health, Kaohsiung Medical University, Kaohsiung, Taiwan.
Chu
Y-T
YT
Chen
W-Y
WY
Feng
W-W
WW
Shih
N-H
NH
Hsiang
C-H
CH
Ko
Y-C
YC
D000328:Adult; D001249:Asthma / Q000097:blood / Q000235:genetics*; D002648:Child; D005192:Family Health; D005260:Female; D005787:Gene Frequency / Q000235:genetics; D020022:Genetic Predisposition to Disease / Q000235:genetics; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D050856:Interferon Regulatory Factor-1 / Q000235:genetics*; D007371:Interferon-gamma / Q000235:genetics*; D015810:Linkage Disequilibrium / Q000235:genetics; D008297:Male; D010641:Phenotype; D011110:Polymorphism, Genetic / Q000235:genetics*; D013624:Taiwan
C494257:IRF1 protein, human; D050856:Interferon Regulatory Factor-1; D007073:Immunoglobulin E; D007371:Interferon-gamma