The association of glutathione S-transferase GSTT1 and GSTM1 gene polymorphism with pseudoexfoliative glaucoma in a Pakistani population

Department of Biosciences, COMSATS Institute of Information Technology, Islamabad, Pakistan.
Molecular vision (Impact Factor: 1.99). 10/2010; 16(229-31):2146-52.
Source: PubMed


The aim of the present study was to investigate the association of glutathione S-transferase GSTT1 and GSTM1 genotypes with pseudoexfoliative glaucoma (PEXG) in a group of Pakistani patients.
Multiplex polymerase chain reaction was used to study the GSTT1 and GSTM1 polymorphisms in 165 PEXG patients and 162 unaffected controls.
In the current study we describe a significant gender-specific association of GSTT1 and GSTM1 null genotypes with PEXG. The three null genotype combinations (i.e., T1M0, T0M1, and T0M0) were found at significantly higher frequencies in the PEXG patients as compared to the controls (χ(2)=21.82, p<0.001). This association was specifically related to the female patients (χ(2)=35.63, p<0.001); no such association was seen in the male patients (χ(2)=2.28, p>0.05).
The results suggest that there is a significant involvement of the GSTT1 and GSTM1 polymorphisms in female Pakistani patients having PEXG, which suggests a possible gender-specific impairment of detoxification in this group.

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    • "DNA was isolated, using a phenol-chloroform protocol (Khan et al., 2010). Isolated DNA was electrophoresed on 1% agarose gels and stained with ethidium bromide. "
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    ABSTRACT: Deletions in GSTM1 and GSTT1 genes are considered to be a risk factor for cancer development but the exact location of these deletions in the genome was unknown. Three main objectives of the current study were to: (a) identify the boundaries of these deletions in the human genome, (b) screen homozygous (-/-) and heterozygous (+/-) deleted, as well as homozygous present (+/+) individuals using PCR assays, (c) detect associations of pharyngeal (PC) and laryngeal cancer (LC) with the respective genotypes. In total, 102 PC and 92 LC patients were screened and compared with 150 controls. PCR mapping and sequencing revealed a 6 kbp deletion for GSTM1 and a 9 kbp deletion for the GSTT1 gene. The mean age of PC cases was 48.1 (±16.7) years; for LC cases it was 48.5 (±17.4) years and for controls 46 (±17.7) years. The OR (odds ratio) for the GSTM1 null genotype in PC and LC cases was 10.2 and 1.0 (95% CI 5.04-20.7 and 1.1-1.7) respectively. Similarly, for GSTT1 the OR was 4.02 with a 95% CI of 2.3-7.1 in PC cases. For LC cases the OR was 0.8 with 95% CI of 0.4-1.7. A non-significant number of LC and PC patients had heterozygous deletions of GSTM1 compared to controls (OD 0.5, 95% CI 0.2- 1.6 and OR 0.5, 95% CI 0.2- 1.5 respectively). The GSTT1 gene also showed a non-significant association in PC (OD 0.9, 95% CI 0.4-1.9), as well as in LC patients (OD 0.7, 95% CI 0.3-1.7). The homozygous genotype was significantly associated with PC and LC, whereas the heterozygous was not so. The GSTM1 (-/-) and GSTT1 (-/-) genotypes are a risk factor for LC and PC, whereas the (+/-) genotypes are not.
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    • "Polymorphisms of GST have been detected in POAG [52], cataract [53], and exudative age-related macular degeneration [54]. However, in patients with PXG of Turkish [55], Swedish [56], and Arab [57] populations, no significant association was noted. Recently, it was shown that the M0 and T0 phenotype of GST is strongly associated with PXG in female Pakistani patients [56]. "
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    ABSTRACT: Pseudoexfoliation syndrome (PXS) is a systemic condition with eye manifestations. In the eye, pseudoexfoliation material deposits on various structures of the anterior segment. The nature of this material is mostly fibrillar with fibers made up of microfibrils and coated with amorphous material. The composition of these fibrils is diverse and includes basement membrane components as well as enzymes involved in extracellular matrix maintenance. Pseudoexfoliation is the most common cause of secondary open-angle glaucoma (pseudoexfoliation glaucoma, PXG) worldwide. The goal of this review is to summarize our knowledge on the genetics of this systemic disorder and its resultant ocular manifestations. PXS familial aggregation suggests genetic inheritance. PXS has been strongly associated with single nucleotide polymorphisms (SNPs) of the lysyl oxidase-like 1 (LOXL1) gene on chromosome 15q24.1. Two of these SNPs confer a higher than 99% population attributable risk for PXS and PXG in the Nordic population; however, they carry different risks in different populations. The high risk haplotypes also vary among different populations. LOXL1 is one of group of the enzymes involved in the cross-linking of collagen and elastin in the extracellular matrix. Its function in connective tissue maintenance has been confirmed in mice; however, its actual role in PXS remains unclear. Contactin-associated protein-like 2 also has a strong genetic association with PXS in a German cohort and is an attractive candidate molecule. It encodes for a protein involved in potassium channel trafficking. Other candidate genes linked to PXS include lysosomal trafficking regulator, clusterin, adenosine receptors, matrix metalloproteinase-1 (MMP1), and glutathione transferase. These genes may be modifying genes for development of PXS and PXG.
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    • "In previous studies we have identified significant associations with polymorphisms in the glutathione S-transferase (GSTT1 and GSTM1) [21] and tumor necrosis factor alpha (TNF-α) [12] with PEXG. Among these higher OR was observed for TNF-α (8.37) as compared to LOXL1 (6.98), GSTT1 (4.26), and GSTM1 (3.81), the combined effect of all these genes probably have a significant contribution in causing PEXG in the Pakistani cohort. "
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