Frequency of glutathione S-Transferase M1, T1 and P1 genotypes and their combinations in northern West Bengal, India: Implications for disease association

Abstract

Glutathione S-Transferases (GSTs) are important xenobiotic-detoxifying enzymes in animals. Polymorphisms in GST M1, GST T1, and GST P1 genes are common within human populations and have been linked to several multi-factorial diseases, including carcinogenesis. The present study aimed to determine the genotypic frequencies of M1, T1, and P1 in the healthy individuals (N = 332) of the northern region of West Bengal, India and to compare the frequencies with different populations studied elsewhere. Genotyping of the M1 and T1 alleles was performed using multiplex-PCR and the polymorphism of P1 allele was studied by PCR-RFLP using Alw261 restriction endonuclease. The M1 and T1 null genotypes were found in 34.9% and 27.4% individuals respectively and 9.9% of individuals were found to be double-null genotypes. The genotypic frequency of P1 revealed that 62.2% of individuals had wild type Ile/Ile genotypes, 29% were heterozygous Ile/Val and 8.7% individuals were homozygous Val/Val. There seemed to be no association between the presence of M1 and T1 alleles with any P1 genotypes (p < 0.05). While frequency of the M1 was found to be similar to most of the Indian populations, T1 was found to be different from other Indian populations. M1 and T1 frequencies are found to be similar to North-East Indian population but were higher than that found in other Indian populations. Given the importance of the alleles in detoxification of pesticides, drugs and carcinogenesis and the preponderance of null genotypes in human disease conditions, this study approaches to delineate demographic indicators that may help future investigations in pharmacological, clinical and genetic association studies.