Glutathione-S-transferase gene polymorphisms (GSTT1, GSTM1, GSTP1) as increased risk factors for asthma.
OBJECTIVE
Asthma is a complex multifactorial disease with an obvious genetic predisposition, immunological aberration, and involvement of noxious environmental factors. Polymorphisms of the glutathione-S-transferase (GST) genes are known risk factors for some environmentally-related diseases. In the present study, the hypothesis that polymorphisms in the GSTT1, GSTM1 and GSTP1 genes are associated with atopic and nonatopic asthma was examined.


METHODS
The study population consisted of 103 unrelated healthy individuals and 101 patients with bronchial asthma (64 atopic, 37 nonatopic). Asthma was diagnosed according to the American Thoracic Society statement. Genotyping of polymorphisms in the GSTT1, GSTM1 and GSTP1 genes was performed using real time polymerase chain reaction with a Light Cycler instrument and hybridization probes in combination with the Light Cycler DNA master hybridization probes kit.


RESULTS
Patients with atopic asthma (34.4%) had a higher prevalence of the GSTT1 null genotype than the nonatopic asthma patients (13.5%; OR = 3.83; 95% CI, 1.24-11.78). Asthma patients (63.4%) had a higher prevalence of the GSTM1 null genotype than the control group (40.8%; OR = 2.34; 95% CI, 1.31-4.20). Subjects with the GSTP1 homozygous Val/Val genotype had a 3.55-fold increased risk of having atopic asthma compared to nonatopic asthma (OR = 3.55; 95% CI, 1.10-12.56).


CONCLUSIONS
These results suggest that the GSTT1 and GSTM1 null genotypes and the GSTP1 Val/Val polymorphism may play important roles in asthma pathogenesis. It is possible that intermediate electrophilic metabolites, arising in the first phase of detoxification, are not metabolized by GST enzymes in asthmatic patients and are not excreted. These intermediate metabolites may damage cells and generate oxidative stress, and so contribute to the pathogenesis of asthma.
Tamer
Lülüfer
L
Deparment of Biochemistry, Medical Faculty, Mersin University, Mersin, Turkey. lutamer@yahoo.com
Calikoğlu
Mukadder
M
Ates
Nurcan Aras
NA
Yildirim
Hatice
H
Ercan
Bahadir
B
Saritas
Emel
E
Unlü
Ali
A
Atik
Ugur
U
D001249:Asthma / Q000453:epidemiology* / Q000235:genetics*; D016022:Case-Control Studies; D005260:Female; D005828:Genetics, Population; D005838:Genotype; D051549:Glutathione S-Transferase pi; D005982:Glutathione Transferase / Q000235:genetics*; D006801:Humans; D007527:Isoenzymes / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D015995:Prevalence; D012307:Risk Factors; D014421:Turkey / Q000453:epidemiology
D051549:Glutathione S-Transferase pi; D005982:Glutathione Transferase; D007527:Isoenzymes; C413545:glutathione S-transferase T1; C496556:GSTP1 protein, human