Evaluation of glutathione S-transferase P1 genetic variants affecting type-2 diabetes susceptibility and glycemic control

Abstract

Introduction: Type 2 diabetes mellitus (T2DM) is associated with increased production of reactive oxygen species and a reduction in antioxidant defenses leading to oxidative stress. Glutathione S-transferases (GSTs) modulate oxidative stress. The present cross-sectional study was aimed at investigating the association between the GSTP1 gene polymorphism and T2DM and to clarify their effect on the glycemic control parameters. Material and methods: From the Egyptian population, we enrolled 112 T2DM patients and 188 healthy controls matched for age, sex and origin. Serum lipid profile, blood-glucose level, glycated hemoglobin (HbA 1c) and body mass index (BMI) were measured. DNA was extracted from the blood samples. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to measure GSTP1 Ile 105 Val gene polymorphism of study participants. Results: The frequency of the Val allele in exon 5 of the GSTP1 gene in patients with T2DM was higher than that observed in healthy controls (15.2% vs. 9.6%); the difference was considered statistically significant when compared to Ile allele carriers (p = 0.03). The presence of the GSTP1 heterozygous mutant allele Ile/Val was more common in subjects with T2DM than in the control group (30.4% and 19.2%, respectively; p = 0.02). Variation in the GSTP1 gene was associated with BMI ( p = 0.02) and not associated with glycemic control parameters (fasting serum glucose and HbA 1c) or smoking-related risk of T2DM. Conclusions: GSTP1 gene polymorphism may play a significant role in increasing the susceptibility to and risk of T2DM and obesity regardless of smoking status and had no apparent effect on HbA 1c in patients with diabetes mellitus. Copyright © 2012 Termedia & Banach.