Polymorphism of glutathione S-transferases as genetic risk factors for the development of complications in type 2 diabetes mellitus

Background

Diabetes is characterized by chronic hyperglycemia that produces dysregulation of cellular metabolism and result in excess free radical production and oxidative stress. Glutathione S-transferases (GSTs) are a family of multifunctional enzymes that work as antioxidants. Therefore, diminished expression of GSTs may result in a reduced body defense against oxidative stress, followed by development of diabetic complications.

Objectives

To investigate the possible association between GSTM1 and GSTT1 polymorphism and the occurrence of complications in type 2 DM and to study the other risk factors for complications in DM.

Methods

Twenty noncomplicated type 2 diabetic patients and 40 complicated type 2 diabetic patients were enrolled in the study. The GSTM1 and GSTT1 genotypes were identified by polymerase chain reaction of peripheral blood DNA samples. Analysis of data was done by using SPSS (SPSS, Chicago, Ill).

Results

The frequencies of null GSTM1 and GSTT1 genotypes were 55% (11/20) and 40% (8/20), respectively, in noncomplicated DM group. The frequencies of null GSTM1 and GSTT1 genotype in complicated DM group were 57.5% (23/40) and 60% (24/40), respectively. The null GSTT1 genotype was more prevalent in the group of complicated DM with odds ratio (odds ratio, 2.3; 95% confidence interval, 0.75-6.7) when compared with noncomplicated DM.

Conclusion

Our data provide evidence that diabetics with null GSTT1 genotypes are substantially at higher risk for developing complications.