A preliminary study on the influence of glutathione S transferase T1 (GSTT1) as a risk factor for late onset Alzheimer's disease in North Indian population

Abstract

Introduction: Oxidative stress plays key role in pathogenesis of Alzheimer's disease. Glutathione S-transferases (GSTs), a family of phase-II isoenzymes, play a critical role in providing protection against electrophiles and products of oxidative stress. Among different classes of GSTs, GSTM1 (Mu) and GSTT1 (theta) are found to be genetically deleted which results in decreased expression of the concerned enzyme. This study aims at preliminary analysis of the frequency of deletion of GSTM1 and GSTT1 and their association with late-onset Alzheimer's disease.

Material and methods: In this study, association of the deletion type polymorphism of GST M1 and T1 as possible risk factors for dementia of Alzheimer's type was studied in 50 patients and 100 controls. Dementia was diagnosed by Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) criteria, Mini Mental State Examination (MMSE) and Clinical Dementia Rating (CDR) scale. Genotyping was done by multiplex Polymerase Chain Reaction (PCR). Associations between null genotype of either GSTM1 and GSTT1 or both with Alzheimer's disease were analyzed by Chi-Square test.

Results: Deletion of GSTT1 was found significantly associated with Alzheimer's disease (χ(2)=5.08, p=0.02*).

Conclusions: The odds of Alzheimer's disease in null GSTT1 is found to be increased by 2.47 times in comparison to positive GSTT1.